The Ebola outbreak in Central Africa was declared a public health emergency of international concern in May, and since then, over 900 suspected cases and 200 deaths have been reported in the Democratic Republic of the Congo (DRC) and Uganda.

With the majority of cases impacting the DRC, this marks the country's 17th Ebola outbreak since the discovery of the virus on the Ebola River in 1976. Most of these outbreaks were caused by the highly lethal Zaire virus, a species of Ebola virus that now has approved treatments and vaccines.

This newest outbreak, however, is being caused by the Bundibugyo virus, a more recently discovered species that is less lethal than Zaire but has no approved vaccines or treatments.

According to modeling published in the Morbidity and Mortality Weekly Report, this epidemic has the potential to become one of the largest Ebola outbreaks on record. It could exceed 20,000 cases in the next three months if effective intervention measures are not taken. Such efforts are underway, but they're complicated by conflict in the region and a dearth of international aid and health infrastructure.

Vaccines can help control Ebola outbreaks, as well as prevent future ones, by enabling health officials to inoculate the close contacts and potential contacts of confirmed and probable cases. Alternatively, all individuals in a given neighborhood or village might be vaccinated, if an outbreak is fairly concentrated. So now, a major effort is underway to craft brand-new vaccines for the Bundibugyo virus.

"The goal is to get a safe and effective Bundibugyo vaccine developed as quickly as possible," Dr. Richard Hatchett, CEO of the Coalition for Epidemic Preparedness Innovations (CEPI), told Live Science in an email.

Different virus, different challenge

Since the 2014-2016 Zaire virus epidemic ‪—‬ the largest Ebola outbreak ever recorded ‪—‬ scientists have learned a lot about how to control these epidemics. Tools such as rapid diagnostics, contact tracing, isolation, infection prevention, safe burials and prompt clinical care are key to reducing transmission and saving lives.

However, according to Dr. Anne Rimoin, chair of infectious diseases and public health at UCLA, there's much less field experience for this particular outbreak, as there have been only two recorded Bundibugyo outbreaks to date.

In addition, the Bundibugyo virus may have had a big head start before it was detected. Experts suspect that, although the outbreak was declared in mid-May, it likely began in February.

If new vaccines are approved, they could help to curb the outbreak using strategies like "ring vaccination." Through a combination of surveillance, contact tracing and rapid vaccination, health officials can vaccinate the close contacts of a person with a confirmed infection, thereby creating a "ring of protection." Potential contacts, and contacts of people with probable cases, can also be vaccinated under this strategy.

Other strategies include the targeted vaccination of populations with the highest transmission rates or phased rollouts of the vaccine that prioritize those at greatest risk of exposure. Even vaccination after exposure, if done quickly, can reduce the risk of severe illness and death.

Global efforts accelerate vaccine development

Scientists and vaccine manufacturers are now racing to design, test, manufacture and deploy vaccines that could help prevent this outbreak from persisting for several years, as previous outbreaks have.

CEPI, a global partnership to accelerate the development of vaccines and treatments against epidemic and pandemic threats, recently announced its support for the development of three vaccine candidates from three institutions: the International AIDS Vaccine Initiative (IAVI), the pharmaceutical company Moderna, and the University of Oxford. The vaccines will be manufactured by the Serum Institute of India.

"We are supporting three different vaccine platform technologies," Hatchett said. "All of these technologies have also been used to develop early-stage candidate vaccines targeting viruses that are closely related to Bundibugyo, so we have a lot of information about how they perform against other Ebolaviruses."

The IAVI vaccine employs rVSV vaccine technology, similar to what is used in the vaccine against the Zaire virus. rVSV stands for "recombinant vesicular stomatitis virus," and rVSV-based vaccines contain a weakened flu-like virus normally found in animals. This virus is tweaked so it makes proteins belonging to the target, in this case, Bundibugyo virus.

Previous Zaire vaccines made with this technology showed 95% to 100% effectiveness in preventing Ebola disease after just one dose ‪—‬ a feature that can be essential in controlling an outbreak.

Oxford's vaccine is using the same technology that forms the basis of the Oxford-AstraZeneca COVID-19 vaccine. Called the ChAdOx1 platform, it uses a harmless version of a common cold virus that infects chimpanzees as its base. This platform is easier to adapt to new strains than rVSV technology, and while rVSV vaccines need to be frozen, it can be transported at refrigerated temperatures.

Moderna — whose mRNA vaccine against COVID-19 was the first to enter human trials — is now using the same technology to design a Bundibugyo virus vaccine. This platform uses mRNA, a molecular cousin of DNA, which gives cells instructions to make small pieces of an inactive viral protein. Because of their production speed and design flexibility, mRNA vaccines have become the best way to rapidly design vaccines against specific viral species.

Preparing the vaccines

Once designed and tested in the lab, the vaccines will move quickly to early-stage clinical trials, in which they will be tested on a small group of healthy volunteers, according to a CEPI statement. These vaccine platforms have already been safely used against similar viruses in both trials and real-world scenarios.

If the safety trials are successful, late-stage trials will begin, with the goals of testing more volunteers and generating enough data for emergency use authorization and production.

According to the World Health Organization (WHO), this could take seven to nine months. The CEPI coordination effort aims to accelerate this timeline by providing funding for the late-state clinical trials. In previous outbreak scenarios, vaccine production often happens at the same time as safety testing to ensure quick deployment.

It is unclear which vaccine might be the most effective or deployed first, although the WHO thinks the IAVI vaccine is likely the most promising. In the meantime, coordinated efforts on the ground will likely make the biggest impact on how the outbreak progresses in the immediate future, experts told Live Science.

Deploying vaccines in an outbreak zone like the DRC presents many challenges. The DRC generally relies on the import of vaccines, but many regions don't have the refrigerated storage facilities required for certain vaccines. If they do, unreliable electricity grids and poor road networks still make it difficult to keep vaccines cold during transport. Vaccine hesitancy can also be high in certain areas.

"We have better tools and better knowledge than we had a decade ago, but all these tools only matter if they reach the front lines quickly, and if communities trust the response," Rimoin said. "So far, we've got a lot of issues with trust in this area."

While vaccines are great tools, researchers and responders must be realistic about timing, Rimoin added.

"These are certainly not going to be tools that are ready to change the course of the outbreak tomorrow," Rimoin said. "The response is going to be depending on the basics: finding cases and isolation, contact tracing, protecting healthcare workers and building community trust."

This article is for informational purposes only and is not meant to offer medical advice.

An Ebola epidemic in Central Africa has been declared a "public health emergency of international concern" by the World Health Organization (WHO).

As of May 22, over 800 Ebola cases have been reported in the Democratic Republic of the Congo, including more than 180 deaths; these counts include both suspected and laboratory-confirmed cases of the disease. There are also two confirmed cases and one death in Uganda, specifically among people who had recently traveled to the DRC.

A number of factors are making this outbreak very challenging to contain, experts told Live Science — here's what to know.

Current Ebola outbreak

WHO officials suspect the Ebola outbreak centered in the DRC may have begun about two months ago. The earliest suspected death occurred April 20, and it was likely followed by a superspreader event at a funeral or healthcare facility, officials say. Reuters also reported that medical personnel failed to escalate the first patient's samples for further tests after they came back negative one type of ebolavirus.

That virus — known as Ebola virus, or Zaire ebolavirus — is the most common culprit behind Ebola disease outbreaks and deaths. There are two other viruses known to cause outbreaks of Ebola disease: Sudan virus and Bundibugyo virus. The latter is driving the current outbreak.

With only a handful of travel-related cases in Uganda, as well as one American receiving care in Germany after being infected in Congo, the outbreak remains concentrated in the DRC. The WHO anticipates a high risk of international spread, though, which prompted the agency's leader to make an emergency declaration without first convening a committee to discuss the decision.

"In our view, the scale and speed of the epidemic demanded urgent action," WHO Director-General Tedros Adhanom Ghebreyesus said May 19.

A virus with no vaccine

Part of the challenge with containment is that there is no effective vaccine against Bundibugyo virus, the germ driving this outbreak.

There are approved Ebola vaccines. "However, these vaccines have been designed specifically to address the Zaire ebolavirus," which has historically caused more outbreaks than Bundibugyo virus has, said Dr. Madeline DiLorenzo, clinical coordinator of infectious diseases operations and an associate hospital epidemiologist at New York University (NYU) Langone's Tisch Hospital. The largest Ebola outbreak to date, which happened from 2014 to 2016, involved the Zaire ebolavirus.

Zaire ebolavirus and Bundibugyo virus are genetically distinct, sharing only about 60% to 70% of their genetic material. The protein targeted by the existing Ebola vaccines is encoded by a specific gene, and that gene's sequence differs between the two viruses, DiLorenzo explained.

Studies suggest that immune responses against filoviruses — the family of viruses that includes Zaire ebolavirus and Bundibugyo virus — show limited cross-reactivity, meaning the immune response is narrowly focused on just one type of virus. So the Zaire-targeting vaccines likely wouldn't help in this outbreak.

WHO officials have said there is a promising experimental vaccine against Bundibugyo virus, but there are no doses available for a clinical trial. It could take six to nine months to manufacture those doses, the WHO estimates. Another vaccine in development could take two to three months to produce, but its efficacy is unknown because scientists are still waiting on results from lab-animal tests.

In Ebola disease outbreaks, vaccines are used for ring vaccination, in which people exposed to a suspected or confirmed case are inoculated against the disease. They can also be used for "targeted geographic vaccination," in which everyone in a given area is vaccinated because the outbreak is relatively concentrated there or contact tracing is too difficult to conduct. Without a Bundibugyo vaccine, both of those strategies are currently off the table.

Lack of diagnostics and treatments

Ebola disease can be difficult to spot in its early stages, in part because the first symptoms are fairly generic: fever, fatigue, malaise, muscle pain, headache and sore throat. These symptoms appear within two to 21 days of exposure to an ebolavirus.

There are tests for Bundibugyo virus that look for the virus's genetic material in bodily fluids; this approach is known as PCR testing. "However, it is not widely available for the Bundibugyo virus, making it difficult to diagnose and, as a result, contain the virus," Dr. Jill Weatherhead, an associate professor of infectious disease and tropical medicine at Baylor College of Medicine, told Live Science in an email.

Even when such tests are available, it can take several days after a patient develops symptoms for the virus to be detectable in blood, DiLorenzo noted, so repeat testing can be necessary. The recommended samples for Ebola tests are whole blood or plasma for living patients and an oral swab for deceased individuals, the WHO says.

There are additional tests that can detect Bundibugyo virus, including some that determine whether a sample contains a filovirus that infects humans in general, without specifying which one is present. These rapid tests look for specific viral proteins. However, these tests are less sensitive and "may not pick up specific proteins associated with Bundibugyo," DiLorenzo said. "This may have contributed to delayed detection of the current outbreak in the DRC."

On top of these diagnostic challenges, there are no specific antiviral treatments for Bundibugyo virus. There are lab-made antibodies approved for Zaire ebolavirus, and they improve survival by binding to the virus's surface and blocking it from infecting cells. Similar treatments for Bundibugyo virus haven't progressed beyond lab research or early-stage human safety studies, Weatherhead said.

Conflict, declining foreign aid hinder containment

In the absence of vaccines and treatments, other strategies, such as quarantining close contacts of infected people, become key to containing the outbreak, Weatherhead said. Clinicians treating patients with suspected or known cases should also follow strict infection-prevention-and-control protocols to prevent further spread, she added.

Ebola spreads via contact with infected blood and other bodily fluids, as well as contaminated surfaces or materials, such as clothing and bedding. This means using personal protective equipment to block splashes or other contact with infected materials, among other protocols.

The strategies available to contain this outbreak — finding and isolating cases and employing tight infection-control protocols — require public health infrastructure to execute. But in the DRC, that infrastructure is severely compromised. The outbreak's epicenter is the Ituri province in the northeastern DRC, which has "experienced armed conflict for decades, making it challenging for health systems to function optimally there," DiLorenzo said.

Joshua Walker, director of programs of the Congo Research Group at NYU's Center on International Cooperation, told Live Science via email that the circumstances of the current outbreak resemble a 2018-2020 outbreak that centered on the North Kivu province, which borders Ituri to the south.

This time around, several cases have been reported in both North and South Kivu provinces, parts of which are essentially partitioned between the DRC government and a Rwanda-backed rebel group, called M23. And there's been increasing violence among armed groups in Ituri in recent months, Walker said. Meanwhile, development assistance for healthcare in the area has fallen substantially in recent years. Together, these factors "will make access and coordination of a single response more difficult," he said.

Recent cuts to foreign aid are only making things worse, Dr. Manenji Mangundu, DRC country director for Oxfam, which is coordinating on-the-ground responses to the outbreak, told Live Science in an email.

"USAID [the U.S. Agency for International Development] was the main donor in the DRC and many aid organizations depended on its funding to deliver life-saving support in a country already devastated by conflict," Mangundu said. "When USAID was shuttered last year, eastern DRC lost around 70% of its humanitarian aid."

More funding cuts from other donors followed, leading to the closure of medical centers, declines in medical supplies and community health workers, and reduced capacity to deal with outbreaks.

"Funding cuts directly do not cause outbreaks, but they do weaken the very systems that are meant to prevent small crises from becoming larger crises," Mangundu said.

In Ituri, residents have been repeatedly displaced due to the conflict and must shelter in crowded schools and churches with limited access to clean water, sanitation and healthcare. Funding cuts only compound these existing problems, he said.

In this setting, it can also be difficult to convince people to adopt safety measures to limit the spread of Ebola, he added. For example, "communities remain attached to their deceased relatives and continue to handle the bodies, which increases the risk of transmission."

Lessons from past outbreaks

Walker noted that the international response to the current outbreak will shape how it evolves.

"The 2018-2020 Ebola response effectively sidelined the local Congolese health system, viewing it as too fragile or weak to be an effective partner," he said, citing his past research. So the response was largely orchestrated by outsiders to local communities, which fostered suspicion.

"One hopes," Walker concluded, "that there have been some hard lessons learned by the international community since the last major outbreak."

As global health leaders warn that this outbreak could swell to impact more countries, Mangundu emphasized that much more support is needed to snuff out the epidemic in the DRC.

"There is capacity in the country to respond, but there are not enough resources to help control and prevent the spread," he said. "We need to fund humanitarian aid and support the people of DRC at this time before a preventable crisis turns into one with far wider, global consequences."

This article is for informational purposes only and is not meant to offer medical advice.

Catching COVID-19 during pregnancy significantly raises the risk of the blood-pressure disorder preeclampsia — but getting vaccinated protects against this serious pregnancy complication, new research finds.

Studies have consistently shown that COVID-19 can worsen pregnancy outcomes. The new findings suggest that, during the pandemic, the coronavirus infection raised the risk of preeclampsia by 45% among pregnant women who caught it, compared to those who did not. Unvaccinated women who caught COVID-19 saw their risk rise by 78%.

Vaccination, meanwhile, lowered the risk of preeclampsia. In people who completed both an initial COVID-19 vaccine regimen and got an updated booster shot, the risk fell by 33%, overall. And it fell by 58% among people with preexisting medical conditions, like diabetes, who got a booster dose.

If these findings are confirmed, they would be a "breakthrough" in understanding the potential links between preeclampsia and viruses, co-lead study author Dr. José Villar, a professor of perinatal medicine at the University of Oxford, told Live Science.

"A protective effect"

About 3% to 8% of pregnant people develop preeclampsia, typically in the second half of pregnancy or shortly after childbirth. Preeclampsia is marked by persistent high blood pressure and, often, protein in the urine, which is a sign of kidney damage. It can also cause vision problems, vomiting, severe headaches, or sudden swelling of the face, hands or feet.

Preeclampsia can cause serious complications, including damage to the liver and kidneys, strain on the heart, and disruption to the placenta's blood supply. It can sometimes progress to eclampsia, which involves brain swelling, seizures or coma. Both preeclampsia and eclampsia can be life-threatening for both the mother and the baby.

Scientists don't know exactly what causes preeclampsia. There's some research to suggest it arises from abnormal development of the placenta, but it's not completely clear whether placental dysfunction drives preeclampsia or is a consequence of it. That said, there is emerging evidence that viral infections, such as COVID-19, may play a role in some cases by triggering changes in the immune system and causing blood-vessel dysfunction, the key process behind preeclampsia symptoms.

Villar's team speculated that COVID-19 vaccines might help curb that risk by lowering the odds of COVID-19 infection and severe illness. They also theorized that vaccination may boost the immune system overall, thereby protecting against other infections and damage to the blood vessels.

For the study, which was published Feb. 18 in the journal eClinicalMedicine, the researchers analyzed data from more than 6,500 women in 18 countries who were pregnant between 2020 and 2022. One-third of the participants were diagnosed with COVID-19 during pregnancy. About 58% were unvaccinated for COVID-19 at the time their data was gathered. Among the remaining women, about 31% got a booster dose in addition to completing their original vaccination series.

Vaccination seemed to offer a "protective effect" against preeclampsia, the researchers said, and booster shots added an extra defense. Notably, women who got booster shots also had lower rates of poor pregnancy outcomes overall — measured as an index score that included events like preterm birth, admission to an intensive care unit, and more — compared with unvaccinated women.

That's in line with research published in 2024 that found women who got at least one COVID-19 shot were less likely to have preterm births, experience stillbirth, or have a baby who was small for their gestational age than unvaccinated people were.

"Vaccinations are safe and are protective for several risks," said Dr. Elena Raffetti, an assistant professor at the Karolinska Institute in Sweden and first author of the 2024 report. "There was not at all an increased risk of preeclampsia among women who were vaccinated," added Raffetti, who was not involved in the new study.

The authors of the latest study emphasized that their findings support current vaccine guidance. The American College of Obstetricians and Gynecologists recommends that pregnant people get an updated COVID-19 vaccine at the earliest opportunity — either while trying to get pregnant, during any trimester of pregnancy, or while breastfeeding or in the postpartum period.

The new analysis does have some limitations. For example, while the researchers tried to control for factors that could influence the results — such as the women's ages, smoking history or health issues linked to preeclampsia, such as previous high blood pressure and diabetes — Villar said there may be other differences between the vaccinated and unvaccinated groups that contributed to their risks.

The study authors said future research into preeclampsia's causes should focus on how the immune system responds to both infections and vaccines, and why infections like COVID-19 seem to raise the risk of the condition.

Villar noted that much is still unknown about what causes preeclampsia, meaning any new insight can help researchers understand this "major disease affecting the mother and the fetus."

This article is for informational purposes only and is not meant to offer medical advice.

What if a single vaccine could offer protection against a range of disease-causing bacteria, common allergens and respiratory viruses? A new mouse study highlights an experimental vaccine that could potentially offer that elusive "universal" protection.

As it's been tested only in lab animals, the vaccine must still pass a number of trials in people before it can be proven safe and effective.

The new study, published Thursday (Feb. 19) in the journal Science, describes a nasal-spray vaccine that works differently than most vaccines.

Conventionally, vaccines train the immune system to recognize a specific antigen, such as a protein on a virus's surface. The immune system then trains cells to remember and attack that antigen if they encounter it. This results in a robust, but fairly narrow immune defense — one which can be thwarted if the target antigen mutates over time.

Some scientists are working on vaccines that target antigens that are "highly conserved" between viral strains, meaning the antigen doesn't change much over time and looks similar from virus to virus. Such shots could potentially target many flu viruses or many coronaviruses at once, for example. But the scientists behind the new nasal-spray vaccine took a different approach: Rather than targeting only the "adaptive" immune system, which remembers specific antigens, it also revs up the innate immune system, a generic, first-line defense.

"What's remarkable about the innate system is that it can protect against a broad range of different microbes," senior study author Bali Pulendran, a professor of microbiology and immunology at the Stanford University School of Medicine, said in a statement.

The idea of a vaccine activating both innate and adaptive immunity is not completely new. It's well known that the tuberculosis vaccine, called Bacillus Calmette-Guérin (BCG), triggers this dual protection. In fact, because of that effect, scientists tested whether BCG could offer broad protection against COVID-19 in the early days of the pandemic.

Pulendran and colleagues had previously studied the BCG vaccine in mice and found that the shot caused immune cells in the lungs to spew specific signals. These signals prompted innate immune cells in the lungs to stay active for several months, rather than calming down after just days.

The new nasal-spray vaccine — called GLA-3M-052-LS+OVA — works by mimicking those special signals. It also contains a harmless egg-protein antigen that helps summon the right immune cells to the lungs. The team found that mice given three doses of the vaccine over three weeks were protected against SARS-CoV-2 (the virus that causes COVID-19) and other coronaviruses, the bacteria Staphylococcus aureus and Acinetobacter baumannii, and an allergen from house dust mites for at least three months afterward.

When exposed to these germs and the allergen, vaccinated mice were protected by the primed innate immune response and also quickly mounted an adaptive immune response against the insults. By comparison, unvaccinated mice fared much worse — in response to viruses and bacteria, they showed higher lung inflammation, weight loss and risk of death, and in response to allergens, they had more pronounced allergic reactions and mucus buildup.

"This is a really exciting piece of research," Daniela Ferreira, a professor of respiratory infection and vaccinology at the University of Oxford who was not involved in the study, told BBC News. It could "change how we protect people from common coughs, colds and other respiratory infections" if the results are confirmed in human studies, she said.

Pulendran also emphasized that, so far, the tests of the vaccine have been in lab animals and more work is required to translate the research to humans.

"If it ultimately proves safe and effective in humans, the potential impact could be transformative: simplifying seasonal vaccination and improving readiness for emerging respiratory threats," Pulendran told Genetic Engineering and Biotechnology News. Pulendran thinks two doses of the vaccine would likely be protective in people, according to the Stanford statement.

This article is for informational purposes only and is not meant to offer medical advice.

For most of modern medical history, scientists have framed infectious disease as having two possible outcomes: recovery or death. You either get better, or you do not survive. But this binary has never fully captured reality.

For a substantial number of people, illness does not simply end — it lingers, reshaping and even permanently altering their life trajectories.

Vaccines are critical tools for avoiding these debilitating outcomes, not only because they help prevent individuals from getting sick, but because they also prevent the multitude of post-infectious conditions that can arise months or years later. By undermining the public's confidence in vaccines and cutting research funding, the second Trump administration is not only increasing the risk of infections, but expanding the population left with chronic post-infectious disease — at the very moment science should be mobilized to prevent, diagnose, and treat both.

The COVID-19 pandemic forced the concept of post-infectious conditions into public view.

Long COVID — marked by persistent fatigue, exhaustion after exercise and effort, cognitive dysfunction ("brain fog"), headaches, and a host of other multisystemic symptoms — affects an estimated 10% to 20% of adults and children after their initial infections. For many, these symptoms are not mild annoyances but life-altering disabilities, disrupting their ability to work, attend school, or participate fully in daily life.

While long COVID may feel unprecedented, it is far from novel. What is new is our collective awareness that such a condition exists, and our opportunity to intervene.

History tells a consistent story: major infectious disease outbreaks are often followed by waves of chronic illness in a subset of survivors. After the 1889-1890 pandemic, often called "Russian influenza," physicians documented prolonged post-viral syndromes that they termed "influenza exhaustion." Affected patients reported months to years of fatigue, muscle pain, anxiety, sleep disturbances, depression, and neurologic symptoms. The phenomenon was so widespread that entire medical texts were devoted to describing it.

A few decades later, the 1918 H1N1 influenza pandemic left an even darker legacy. In its wake emerged encephalitis lethargica, a devastating post-infectious condition marked by encephalitis (brain inflammation) and catatonia, a condition that leaves a person unresponsive to the world around them. It also came with profound neurologic impairment and coma-like states in some of those affected.

Between 1919 and 1927, the British Ministry of Health recorded nearly 16,000 cases, with an estimated mortality rate approaching 50%. Of those who survived, only a small fraction fully recovered; many were left with lifelong disability. Children were disproportionately affected — in 1924 alone, more than 1,000 schoolchildren in England had developed the condition, two-thirds of whom never returned to their baseline health.

This pattern repeated throughout the 20th century. During the poliovirus epidemics that swept the Northern Hemisphere, most infected individuals experienced only mild illness, while others developed paralytic disease. But the story did not end with acute infection. Years or even decades later, some polio survivors, regardless of the initial severity of their infection, developed post-polio syndrome. This was marked by progressive muscle weakness, severe fatigue, debilitating pain, and, in some cases, paralysis. The unpredictability of who would be affected, and when, remains one of polio's most unsettling features.

More recently, survivors of the 2002-2004 SARS outbreak experienced what is now known as "Long SARS," with persistent pulmonary disease, muscle wasting, sleep disturbances, fatigue, and cognitive impairment lasting a year or more. SARS, a close relative of SARS-CoV-2, foreshadowed the post-viral syndrome that would follow COVID-19.

And after the 2014-2016 West African Ebola epidemic, many survivors reported chronic eye complications, musculoskeletal pain, neurocognitive deficits, and profound fatigue, despite having already survived a virus with a fatality rate exceeding 40%.

Across time, geography, and pathogens, the lesson is strikingly consistent: surviving an infection does not always mean recovering from it. Knowing that history repeats itself, it becomes clear that prevention is not just a tool for avoiding acute illness, but our most powerful strategy for preventing chronic disease. Simply put, vaccines are indispensable.

Vaccination does more than reduce hospitalizations and deaths. By preventing infection in the first place, vaccines can also prevent the downstream risk of long-term medical problems that we still cannot reliably predict, treat, or reverse. The only proven way to eliminate the risk of post-infectious chronic illness is to avoid the infection altogether.

Yet public confidence in this foundation has been steadily eroded. Conflicting messages from the Health and Human Services Secretary Robert F. Kennedy Jr., politicized health decisions, and policies that stray from evidence have left families — especially those with children — struggling to know whom to trust. This confusion does real harm. It weakens vaccine uptake, increases circulation of preventable diseases, and sets the stage for future waves of chronic illness.

Modern medicine did not become extraordinary by accident. It became extraordinary because scientists and doctors embraced data, rigorous study design, and prevention. Vaccines are among its greatest achievements — not only because they save lives today, but because they spare lives from being permanently altered tomorrow.

While any medical intervention carries a degree of risk, the risks associated with vaccines are minor, and their profound benefit on human health is unmatched.

We are at a pivotal moment, with an unprecedented ability to unify and advance the study of post-acute conditions. Modern technology and communication now make it possible to interrogate their biology in ways that were previously unimaginable. If we have learned anything from more than a century of pandemics, it is this: history does repeat itself. Abandoning vaccines and evidence-driven medicine will not make us freer or healthier. It will, quite simply, make us sicker.

Opinion on Live Science gives you insight on the most important issues in science that affect you and the world around you today, written by experts and leading scientists in their field.

This article is for informational purposes only and is not meant to offer medical advice.

A vaccine designed using "DNA origami" activated more of the key immune cells needed to fight HIV than did traditional vaccines built upon protein scaffolds, a new mouse study found.

"DNA origami" refers to a precisely engineered, three-dimensional scaffold made of folded DNA that can hold and display viral antigens — bits of viruses that the immune system can recognize and attack.

The new mouse study's results, published Feb. 5 in the journal Science, suggest a "potential breakthrough" that could "transform the way we think about active immunotherapies and vaccine design," study co-author Mark Bathe, a professor of biological engineering at MIT, said in a statement.

Why could this origami approach be transformational? The answer may lie in how the DNA-based vaccines are seen by the immune system, compared to traditional vaccines.

How the DNA origami vaccine works

Conventionally, vaccines have relied on weakened or killed viruses to rouse immune cells to make antibodies against proteins found on that virus's surface. By binding to the proteins, the antibodies block the virus from invading human cells and flag the germ for destruction by other immune cells.

This process imparts immunity by prompting the body to make "memory B cells," which linger and get activated much faster if the same pathogen is encountered again.

But nowadays, rather than using whole viruses, many vaccines use only the surface antigens attached to synthetic, virus-like particles. These nanostructures mimic the size and geometry of viruses but cannot cause infection.

Most virus-like particles used today are built using protein scaffolds that the immune system sees as "foreign," so they trigger an "off-target" antibody response against the scaffold itself. In some contexts, this may dilute the responses against the antigen, previous studies suggest.

In the new study, scientists replaced the protein scaffolds with a DNA-based scaffold and, by doing so, sharply reduced those off-target responses. This new vaccine design produced up to three times more of the important memory B cells than state-of-the-art protein nanoparticle vaccines did.

John Moore, an HIV researcher at Weill Cornell Medicine who was not involved in the work, described the study as "elegant." It clearly demonstrates how eliminating scaffold-related immune responses pushes the immune response "in the right direction," he told Live Science.

He cautioned, however, that it remains to be seen whether the same degree of immune focusing will occur in humans.

An edge on the competition?

HIV evades the immune system by constantly reshaping its surface proteins so that antibodies that work against one strain often fail against others. That is why HIV vaccine design has been "incredibly challenging," said Adam Wheatley, an immunologist at the University of Melbourne who was not involved in the study.

What the vaccine needs to produce are "broadly neutralizing antibodies" against the virus, he said. These antibodies lock onto parts of the virus that barely change from strain to strain.

One example of such an antibody is called VRC01, which has been identified in a small number of people living with HIV whose bodies produce broad antibody responses. VRC01 targets a vulnerable region on HIV's outer envelope called the CD4-binding site. This is the "key" the virus uses to enter human immune cells, and it doesn't differ much between strains.

The challenge is that B cells that are capable of producing VRC01-like antibodies are extraordinarily rare in the human body, said Raiees Andrabi, an immunologist at the University of Pennsylvania who was not involved in the work. Activating those elusive cells "becomes an engineering problem," he told Live Science.

To target these rare B cells, the researchers carefully engineered the vaccine using an HIV antigen on the DNA scaffolding. Developed about a decade ago, the antigen they used mimics the CD4-binding site and selectively binds the rare B cells' receptors, thus initiating the production of broadly neutralizing antibodies.

The researchers got the idea to combine the antigen with DNA origami after testing the origami approach in an experimental COVID-19 vaccine. They'd found that the immune system showed virtually no response to the DNA scaffold.

"This property seemed especially useful for a case like HIV, where the B cells of interest are exceptionally rare," first study author Anna Romanov, an immunology researcher at MIT, said in the statement.

They hypothesized that delivering the antigen on a silent scaffold could reduce the competition with other irrelevant B cells, thereby boosting the "on-target" response against HIV. And in the study, they found the silent-scaffold approach had indeed amplified the B cells that produce broadly neutralizing antibodies. (That said, they have not yet assessed how many broadly neutralizing antibodies actually get made; that should be addressed in future work.)

"We were all surprised" that DNA origami outperformed the standard virus-like particles used in eliciting the desired B cell responses, Bathe said.

In general, it's unclear how bad it is for the body to generate an immune response against the scaffold, Wheatley said. But in the case of HIV, the desired B cells are so rare that even a modest off-target response seems to undermine the response against the target antigen.

The road ahead

The engineering of the DNA-origami vaccine was not straightforward; early versions produced weak immune responses. That was partly because, after injection, those vaccines failed to reach specialized immune cells inside the lymph nodes, where B cells train.

To correct this, the team redesigned the DNA particles to pack the HIV antigens more precisely and tightly. This enabled them to be carried into the right regions within the lymph nodes. The researchers also added a molecule to help activate T cells — immune cells help the critical immune response grow. This T-cell recruitment happens naturally with protein-scaffold vaccines.

"I think it is quite striking how efficiently they modified their DNA scaffold in a number of ways to get it to work," Wheatley said. "I guess the major utility of it is [that] it's really tunable."

Beyond HIV, the study authors suggest that DNA origami could be applied to make vaccines against other rapidly mutating viruses, such as influenza, where the effectiveness of the vaccine might be improved by focusing the immune response it triggers.

However, it remains to be seen how well this technique will translate to humans. HIV vaccination is "very difficult" and might have multiple components to help develop the immune response over time, Andrabi explained, adding, "It's not just going to be one or two shots."

However, he said, "they have figured out the first step."

The U.K. has officially lost its measles elimination status, meaning the highly infectious disease has been circulating continuously in the region for at least a year.

Within the past decade, the U.K. has gained, lost and regained its measles elimination status, according to an update posted Jan. 26 by the UK Health Security Agency (UKHSA). It eliminated the disease in 2016 but saw a resurgence in 2018, along with the rest of Europe. It then regained its elimination status in 2021, when precautions taken to stop the spread of COVID-19 also drove down measles rates.

But in the years since, measles rates have rebounded again in the country — and based on data from 2024 that was submitted to the World Health Organization (WHO), the infection is now officially reestablished in the U.K.

Ben Kasstan-Dabush, an assistant professor of global health and development at the London School of Hygiene and Tropical Medicine, called the news "unsurprising."

"Sustained measles transmission reflects a decade-long decline in routine vaccination coverage and the persistent failure in the UK to reach the 95% measles vaccine coverage threshold recommended by WHO," Kasstan-Dabush said in a statement. "Profoundly low coverage in areas such as Hackney [in East London] underscores the unequal distribution of risk and harm to children."

Because measles is so contagious, most of a population must have immunity — either through vaccination or prior infection — to stop the disease from spreading. Measles vaccines are given in a two-dose series, which, once completed, is about 97% effective at preventing measles. To reach herd immunity via vaccination, 95% of a population must have received two doses of the vaccine, the WHO states.

In the U.K., vaccines are not mandatory, but measles vaccination is recommended as part of the National Health Service's national immunization program. Young children were previously offered the measles, mumps and rubella (MMR) vaccine, with the first dose at age 1 and the second at age 3. As of 2026, young children are recommended the MMRV vaccine, which additionally protects against chickenpox (varicella), and are offered doses at 12 and 18 months old. The MMR vaccine is still given to kids born before 2019, as well as adults who have not yet completed their two-dose series.

In 2024, the U.K. reported 92.3% coverage with the first MMR dose and 84.4% with the second, which roughly matched the coverage levels reported in 2023. In recent years, 2016 saw the highest coverage levels, with 95.3% for the first dose and 88.2% for the second. Coverage has fallen steadily since then.

"As history teaches us, elimination can only be achieved and sustained by improving coverage of the MMRV vaccine in children to meet the WHO 95% target and by using all opportunities to catch up older children and adults who missed out when they were younger," the UKHSA statement says.

According to the 2024 data, additional countries within the WHO European Region have lost their measles elimination status, including Spain, Austria, Armenia, Azerbaijan and Uzbekistan.

Meanwhile, Canada lost its measles elimination status in November 2025, and the U.S. is poised to lose its status any day now. In the United States, health officials are currently investigating whether various outbreaks unfolding across the country are linked. If they can confirm that the same outbreak strain has been spreading for a year, the country's measles elimination status will be lost.

Experts have pointed to prominent anti-vaccine advocates, such as Health Secretary Robert F. Kennedy Jr., as contributing to the U.S.' falling vaccine coverage and skyrocketing measles rates. But in mid-January, the principal deputy director of the Centers for Disease Control and Prevention dismissed the issue, saying he wouldn't consider America losing its status to be a significant event.

This article is for informational purposes only and is not meant to offer medical advice.

A new study helps reveal why some vaccines, including those for COVID-19 and influenza, are less effective in older adults than they are in younger people — and it may fundamentally shift our understanding of aging.

Traditionally, scientists have attributed the reduced vaccine response seen in older adults to a decline in the immune system with age. Many have pointed to persistent, low-grade immune activation — a process dubbed "inflammaging" — as one driver of this decline.

But a new study that compared the immune systems of older and younger adults found no consistent increases in biological markers of inflammation with age. Instead, aging appears to reprogram T cells — important immune cells that help train a type of white blood cell, called B cells, to produce antibodies in response to viruses and vaccines.

The findings, published Oct. 29 in the journal Nature, suggest that inflammation may not be as fundamental to the aging process as scientists previously thought.

"We think inflammation is driven by something independent from just the age of a person," Claire Gustafson, an assistant investigator at the Allen Institute for Immunology and one of the lead authors of the study, said in a statement.

Alan Cohen, an associate professor of environmental health sciences at Columbia University who studies aging and inflammation, said the new findings support a more nuanced view of "inflammaging."

The idea that inflammation increases with age "may be true on average in industrialized populations," said Cohen, who was not involved in the work. "But it won't be true for everyone, and it won't be true in every population," he told Live Science.

Cohen cautioned that the participants in the new study were drawn entirely from Palo Alto, California, and Seattle — both highly industrialized areas. Having found significant differences in inflammation between adult populations from Italy, Singapore, Bolivia and Malaysia, he said such findings may not hold up across different environments.

"I certainly wouldn't take this as, 'Oh look, now they've shown definitively there's no change in inflammation with age,'" Cohen said. "I would take it more as, here's an example of a population that doesn't appear to be doing the same things that we have typically expected."

T cell changes are not driven by inflammation

In the interest of improving older adults' responses to vaccines, Gustafson and her colleagues looked at how T cells change with age.

First, they compared younger adults (ages 25 to 35) with an older group (ages 55 to 65, or people at what the researchers call the "cusp of aging.") For two years, the researchers followed 96 healthy volunteers in these age groups, collecting blood samples from each participant eight to 10 times and monitoring their immune systems before and after their annual flu vaccinations. Then, they expanded their research to include a second group of 234 adults ranging in age from 40 to over 90.

To examine the immune system across these groups, the team used single-cell RNA sequencing, which enabled them to look at a type of genetic material called RNA inside each immune cell. RNA reflects which proteins a cell is making at a given moment. The team also used high-dimensional plasma proteomics, which maps the proteins circulating in blood, and spectral flow cytometry,which identifies and counts immune cells by their molecular "fingerprints."

The researchers spotted distinct differences in memory T cells — immune cells that "remember" past infections and help the body respond faster the next time a pathogen shows up.

In older adults, increasing numbers of memory T cells shift into a state that changes how they respond to threats — by changing their interaction with B cells. When memory T cells are not working as they should, B cells become less effective at producing antibodies in response to infections or vaccines, the study found. Meanwhile, the memory T cells of young adults were adept at responding quickly and ramping up the expected antibody response.

These immune changes seem to happen independently of inflammation and of infections with latent viruses, which stay in the body after the initial infection and may go dormant, not causing any overt symptoms. Infections with these viruses, such as cytomegalovirus (CMV), are often blamed for weakening the immune system with age. However, the study found that people under 65 who had experienced a CMV infection at some point in their life did not have signs of faster immune aging or increased levels of inflammatory proteins.

Cohen remains cautious about the study authors' conclusions, noting that the most significant changes in the immune system tend to occur after age 65. "If you don't see a change in inflammation between 25 to 35 versus 55 to 65, is that really because inflammation isn't changing with age, or just because they didn't get old enough to see something?" he questioned.

The researchers said these findings could eventually help scientists design vaccines that compensate for age-related immune changes, thus better protecting older adults. They also think the results could be useful for designing treatments that restore immune function in old age.

This article is for informational purposes only and is not meant to offer medical advice.

On Dec. 31, 2019, the first reports emerged about a mysterious pneumonia of unknown cause circulating in China. On March 11, 2020, the World Health Organization declared COVID-19 a pandemic.

On March 16, the first COVID-19 vaccine entered clinical trials.

And by Dec. 14, members of the American public were getting the first doses of COVID-19 vaccines outside of trials.

The first coronavirus vaccines were paradigm-shifting because they went from conceptualization to mass production in mere months. But they were also unique because they used a new way to stimulate the immune system — one that had been thoroughly studied for decades in order to be ready for deployment at this crucial moment.

The key to these vaccines was messenger RNA (mRNA), DNA's less-famous cousin. The power of the mRNA platform is that vaccines can be produced exceptionally quickly once a pathogen's genetics have been analyzed; conventional vaccine manufacturing takes months or years whereas mRNA vaccines can be made in mere weeks. So while it was once the subject of high school biology classes and niche pockets of biomedical science, mRNA was suddenly thrust into the public eye — and once there, it inspired relentless misinformation and controversy.

While mRNA-based COVID-19 vaccines are the best known application of the molecule, researchers around the world have found additional uses for mRNA technology beyond the realm of vaccines. They're exploring its use for groundbreaking treatments for cancer and autoimmune disease, as well as for gene-editing therapies for genetic disorders. But that promise may be unrealized in the United States, where the federal government has declared war against this promising technology.

This new stance runs counter to the Trump administration's prior embrace of mRNA vaccines.

"We do really have to give President Trump credit for introducing the mRNA platform to the world through his leadership in Operation Warp Speed," said Jeff Coller, the Bloomberg distinguished professor of RNA biology and therapeutics at Johns Hopkins University. "The president should be taking a victory lap." But instead, the second Trump administration is actively dismantling this legacy, Coller told Live Science.

Vaccine skeptic Robert F. Kennedy Jr. now heads the Department of Health and Human Services (HHS), and opponents of both conventional and mRNA-based vaccines hold seats on the country's most influential vaccine advisory committee. Since Trump's inauguration, federal scientists have faced mass layoffs, funding freezes, and memos warning them to disclose their involvement in research areas the administration has targeted, including mRNA vaccines.

These actions had an immediate chilling effect on mRNA research and development in the U.S., Coller told Live Science. And then, in August, HHS canceled nearly half a billion dollars of investment into mRNA vaccine development.

"I was shocked to see this, frankly," said Jordan Green, head of the Biomaterials and Drug Delivery Laboratory at Johns Hopkins, whose lab is developing both mRNA therapies and delivery systems to get the molecule into the body.

The cuts are sending ripples through biotech, making stakeholders question whether it's safe to set up shop in the U.S., or whether their mRNA investments would be better spent abroad. "It's just a shame because it's an unforced error; there's no reason," Green said.

For now, HHS appears to be retreating primarily from mRNA vaccines; it noted "other uses of mRNA technology" would not be affected by the cuts. But "the industry doesn't trust that," Coller told Live Science.

According to Grant Witness, a project tracking scientific grants under the Trump administration, mRNA research unrelated to vaccines has already been hit by grant terminations and funding freezes. So even if it's not being explicitly targeted, it's not necessarily being preserved. The project's database shows that the National Institutes of Health (NIH), part of HHS, terminated grants for projects developing mRNA-based treatments for cancer, Alzheimer's, pulmonary arterial hypertension and HIV, as well as grants for basic research about how mRNA works in healthy and diseased cells.

Here's what the United States stands to lose if the federal government broadly divests of mRNA medicines after spending decades readying the technology for prime time.

Cancer treatment

On a molecular level, mRNA is a close cousin of DNA — and human cells are stuffed with it. These ubiquitous "messengers" copy instructions from DNA and relay them to other locations in the cell — namely, to protein-construction sites where the complex molecules that do most of the work in cells get made. mRNA also performs other key jobs in cells, such as helping control which genes are switched on and to what degree.

For decades prior to the pandemic, dedicated scientists pored over mRNA, learning how this class of molecules works in the body and how it might be leveraged to heal the sick and guard against disease.

"I started doing this when I was like 21, back in the '90s, back when about 10 people on Earth knew what mRNA were," Coller said. Findings from Coller's lab later helped inform the development of Spikevax, the COVID-19 vaccine made by Moderna. But while COVID-19 vaccines are the best-known application of mRNA to date, they're far from the first.

The first mRNA therapeutics company was founded in 1997, and rather than targeting infectious disease, it had its sights set on cancer treatment. Its approach ultimately hasn't panned out in human trials, but in the meantime, other approaches to mRNA-based cancer treatment have gained traction.

Cancer vaccines are a standout example, but in this context, the term "vaccine" is "a bit of a misnomer," said Dr. Vinod Balachandran, a pancreatic cancer surgeon-scientist and director of The Olayan Center for Cancer Vaccines (OCCV) at Memorial Sloan Kettering Cancer Center. Rather than being given preventatively, like a COVID vaccine, cancer vaccines are "given to patients as a treatment; it is a therapy," he said.

These therapies are similar to conventional vaccines in that they train the immune system to recognize antigens, which are substances that act as "red flags" for foreign invaders, toxins or diseased cells. These include, for example, the spike protein of SARS-CoV-2 — the virus that causes COVID-19 — and certain molecules on cancer cells. Balachandran and colleagues have focused on pancreatic cancer, which has a five-year relative survival rate of only 13% — meaning people newly diagnosed with pancreatic cancer are about 13% as likely to survive the next five years compared with the general population.

The researchers have found that, in the rare long-term survivors of pancreatic cancer, the immune system can recognize the cancer and fight off its recurrence. The team hoped to re-create that immune recognition in other patients by analyzing the genetics of their tumors to see what unique antigens they express. They then create customized vaccines that target those molecules.

"We felt at the time [when we started this work] — this is back in 2017 — that the best technology for rapid custom cancer vaccination for patients was to use RNA," Balachandran said. Once you know a given patient's cancer genetics, a personalized mRNA vaccine that targets multiple antigens can be crafted in a matter of weeks. Conventional vaccines that require the antigens to be grown in the lab and purified would take many months to make.

"For cancer vaccination, speed is essential," Balachandran said. "These are patients who are facing deadly cancers, who require rapid treatment. So we do not have the luxury of waiting."

So far, the team has seen some success. In an early-stage trial, they treated 16 patients who had undergone surgery for pancreatic ductal adenocarcinoma (PDAC), the most common form of pancreatic cancer, which has a five-year survival rate of about 10% to 12%, though they fare a bit better when their cancer can be surgically removed.

Within nine weeks of surgery, Balachandran said, each patient's tumor tissue was analyzed and a personalized vaccine was crafted and delivered alongside post-surgery cancer treatments, like chemotherapy. Half of the patients responded to their vaccine, producing immune cells that have persisted for nearly four years so far, and estimates suggest they could last an average of seven years, "with some lasting even beyond a decade," Balachandran said.

The vaccine responders had a significantly lower risk of recurrence in the following three years than those who didn't respond, with six showing no signs of recurrence in that time frame. A mid-stage trial is now testing the vaccine in about 260 people to see how well it delays or prevents recurrence compared with standard treatment.

"Anything we can do to improve outcomes for these patients who really need help I think will be transformative for the field, for them, for their families — it will mean a lot," Balachandran said. "All other immune therapies and all other therapies have largely failed."

In this initial trial, vaccine production took over two months, in part because samples had to be shipped to overseas collaborators at BioNTech. "We are confident this can happen much faster" in the future, perhaps within a month, Balachandran said.

Other scientists are working on off-the-shelf cancer vaccines that can help bridge the gap until a patient gets a personalized one. These vaccines use a mix of mRNA molecules to stir up a generic, first-line immune defense against cancer. In mice with different kinds of solid tumors, researchers led by Dr. Elias Sayour, a pediatric oncologist at the University of Florida, demonstrated that such a vaccine triggers anti-cancer responses by itself. And when used in combination with another cancer treatment, the mRNA mix can boost the effects of that therapy, Sayour's team has found.

That team has now moved on to human patients, with a two-pronged approach: an off-the-shelf cancer vaccine, followed by a personalized one. They have also run trials of personalized vaccines for the deadly brain cancer glioblastoma, finding that the shots mount a strong, targeted immune response against these tumors that are usually difficult for the immune system to "see." Meanwhile, at another lab, scientists are testing a personalized vaccine in late-stage trials for the skin cancer melanoma and non-small cell lung cancers.

Pancreatic cancer has historically been an elusive target for the immune system because, compared to cancers like melanoma, its cells carry relatively few antigens, Balachandran explained. But pancreatic cancer can be targeted with these vaccines. That bodes well for using mRNA approaches to treat potentially many other cancers, and "I think that's really the most exciting take-home," he said.

Beyond cancer vaccines, Green and colleagues are leveraging mRNA to fight the disease in a different way: by forcing tumors to raise their own red flags to the immune system. Using mRNA packaged inside nanoparticles, the researchers introduce immune-cell genes into cancer cells, prompting tumors to expose their antigens and secrete molecules that call immune cells to the area.

"We can program that tumor cell to now act like an immune cell that helps teach other immune cells what its antigens look like, how to recognize it, how to destroy it," Green told Live Science. In mouse models of breast cancer and melanoma, they combined this approach with an existing immunotherapy and found that it helped shrink and clear tumors from the body while also extending survival.

If shown to work in people, "this could just be off the shelf," he said. It would be one injectable that could work on any patient's solid tumor, he said.

Immune reprogramming

In cancer, scientists are exploring different ways to launch an immune attack against tumor cells, whether by igniting a generalized response or enabling cells to spot specific red flags. But in some diseases, the immune system itself is the culprit — and in those instances, mRNA can help rein in turncoat immune cells.

"Autoimmune diseases — type 1 diabetes, multiple sclerosis, Crohn's, colitis — these can be treated with these mRNA and genetic-based therapies," potentially, Green said. The goal of these treatments would be to "tune the immune system" so it stops attacking healthy tissues.

In type 1 diabetes, for example, the immune system attacks beta cells, which make insulin, leaving the body too little of the hormone to control blood sugar. Green and colleagues are in the early stages of developing an mRNA medicine to reprogram the immune system so it better tolerates beta cells, rather than attacking them. They aim to do this by targeting special immune cells in the liver that promote a tolerant environment in the organ.

The liver is constantly exposed to antigens from food and from microbes in the gut, so immune activity is dialed down to prevent an overreaction. The team's idea is to deliver mRNA that codes for beta-cell proteins to the liver, essentially marking those beta-cell proteins as "safe" to the immune system. This, in turn, can increase the number of regulatory T cells that recognize the proteins as safe; regulatory T cells keep other immune cells in check, and could thus help ward off further attacks on beta cells.

"The problem with autoimmunity is that [the immune system] thinks parts of its own body are foreign," so it's trying to attack them, Green explained. The hope is that "we can use these mRNA medicines to train the immune system so that it sees, 'Oh no, this is fine.'" The work is currently in preclinical stages, as the team runs experiments with cells and lab mice to refine their mRNA nanoparticles.

Green calls this approach of fine-tuning specific cells' activity "genetic surgery." Rather than using a "blunter instrument," like immunosuppressive drugs, to broadly suppress the immune system, the surgery makes a precise change to counter only harmful immune activity. In the long run, the lab is looking to apply this same approach to other autoimmune diseases beyond diabetes, such as multiple sclerosis, in which immune cells target myelin, the insulation surrounding nerve fibers in the brain and spinal cord.

Meanwhile, BioNTech has published data from its own early tests of an mRNA vaccine designed to quell autoimmunity against myelin. In mice, the vaccine expanded populations of immune cells that then kept the myelin-attacking cells in check, suppressing their activity without hobbling the immune system as a whole.

Elsewhere, researchers including Dr. Samira Kiani of the University of Pittsburgh School of Medicine and Kathryn Whitehead of Carnegie Mellon University are using mRNA to counter off-the-rails immune responses, such as the extreme inflammation seen in sepsis. Their approach, described in a preprint, packages mRNA inside a tiny bubble of fat called a lipid nanoparticle (LNP), which then ferries the mRNA into immune cells. From there, the mRNA instructs the cells to make proteins called "zinc finger repressors," which latch onto genes and suppress their activity. In this case, they repressed a key gene involved in the immune signaling that can lead to runaway inflammation.

In experiments with cells in lab dishes and with mice, this type of "epigenetic engineering" showed promise as a potential method for tuning the activity of the immune system. One perk of mRNA is that it degrades quickly in the body, the study authors wrote, so in theory, once the harmful inflammation is subdued, the immune system can get back to defending the body against germs.

Gene editing

mRNA is also being used in tandem with the gene-editing system CRISPR to revolutionize treatments for genetic disease.

Classical CRISPR systems use molecular scissors to snip through DNA strands and enable scientists to tweak specific segments of the molecule. And now, a modified system called base editing can be used to precisely change just one "letter" in DNA's code.

But if you want to use CRISPR for gene therapy, you must first get the scissors, as well as a "guide" molecule that directs them to the right spot — into human cells. And, ideally, the scissors enter only the cells you need to edit, said Giedrius Gasiūnas, a senior researcher in the Life Sciences Center at Vilnius University in Lithuania.

That's where mRNA packaged in nanoparticles could be a game changer.

"This technology could be important for in vivo delivery," meaning the delivery of gene editors directly into the body, said Gasiūnas, who is also chief scientific officer of the biotech company Caszyme.

The first CRISPR-based therapy approved in the U.S. involved editing cells outside the body. The therapy treats two blood disorders by disabling a gene called BCL11A; patients have blood-making stem cells removed from their bone marrow, edited in the lab and then returned to their bodies. But this complex treatment involves a month-long hospital stay, during which the edited stem cells give rise to new blood cells. By comparison, mRNA approaches to gene therapy would be easier to administer and thus more likely to be scalable, Gasiūnas said.

mRNA isn't the only vehicle for getting CRISPR therapies into the body. Some existing gene-editing treatments instead use harmless viruses, such as adeno-associated virus (AAV) vectors, and this same approach is being applied to CRISPR in some emerging therapies. But mRNA packaged inside nanoparticles is emerging as a key player in the field.

This application made headlines in the case of KJ, an infant who became the first person to receive a personalized CRISPR treatment. "The CRISPR technology was introduced as an mRNA," Coller said. "That is the critical feature that was necessary to get this to work."

KJ was born with a severe form of carbamoyl phosphate synthetase 1 (CPS1) deficiency, an inherited disease that causes ammonia to accumulate in the body and affects an estimated 1 in 1.3 million people worldwide. The condition arises from mutations in the CPS1 gene, but in different patients, the gene is broken in different ways. To fix KJ's specific mutation, scientists developed a customized gene therapy consisting of a guide and an mRNA that carried instructions for a base editor into his liver cells, where CPS1 is most active.

"The editor is so large that it cannot easily be accommodated by an AAV vector," said Dr. Kiran Musunuru, co-developer of the therapy and a professor at the University of Pennsylvania's Perelman School of Medicine. Because other potential delivery systems are too early in development, "LNPs are currently the best option," Musunuru told Live Science in an email.

The therapy was ready to administer within six months of KJ's birth. By 9 months old, he had received several doses of the therapy and was thriving; he was hitting milestones he may have never reached otherwise, his medical team reported in May. Had he not received the treatment, he would have needed a liver transplant once he got big enough.

Promising technology at risk

When it comes to the future of mRNA medicines in the U.S., vaccines for infectious disease currently have the bleakest outlook due to political barriers being raised around the technology. Among mRNA tech, vaccines have been the primary target of the federal government's ire, despite experts' warnings that abandoning the shots will leave us vulnerable to pandemics.

"It's foolish to condemn mRNA because people didn't like vaccine mandates or mask mandates or whatever they didn't like," Dr. Seth Berkley, an epidemiologist and senior adviser to the pandemic center at the Brown University School of Public Health, told Live Science. "What we need to do is improve upon them [mRNA vaccines] and understand what the best use of them is," which can only be accomplished through investing in further research.

For now, other applications of mRNA don't appear to be a focus for funding cuts, although some projects have nonetheless been caught in the crosshairs of reduced federal spending. For his part, Musunuru told Live Science he's been in discussions with the Food and Drug Administration regarding ways to get more patients access to personalized gene therapies like KJ's, so that the technology isn't used only in a handful of special cases. When asked about potential funding cuts, he added, "Vaccines and therapies are so different that I do not expect the latter to be affected."

Green, however, anticipates that divestments from vaccines would have unanticipated impacts across the field, because mRNA therapies and vaccines are ultimately composed of very similar genetic molecules and delivery systems.

Regarding nanoparticles, "the vaccine development is … at the pioneering edge of this technology platform," Green said. He argues that cuts to vaccine R&D will inevitably undermine the development of nanoparticles that could be really useful in treating cancer or genetic disease. "It's going to set us back in a very broad way," he said.

The hits to vaccine research also aren't happening in isolation. Myriad federal science grants have been terminated or frozen; NIH agencies may be facing steep funding cuts; and the government shutdown ushered mass layoffs across leading health institutions. Sayour, the oncologist whose lab is developing personalized and universal cancer vaccines using mRNA, said federal grants have historically been critical to his research.

"None of this would be possible without the support of the federal government," Sayour told Live Science. "That is most certainly, 100% true." And that goes for every stage of research, from studies in lab dishes to large clinical trials.

These widespread cuts and more-targeted cuts to mRNA vaccines will not only starve the academic environments where new biotechnologies are typically nurtured, Coller said; they will also drive prospective talent, investors and industry stakeholders in the mRNA space away from the U.S. "In biotech, we're going to see, over the next five to 10 years, a significant 'brain drain,' where other countries build up their infrastructure," he said.

Coller knows this because he is a founding member of the Alliance for mRNA Medicines (AMM), a global organization aimed at advancing and advocating for mRNA medicines. In the spring, AMM surveyed over 100 leaders in the field. They primarily represented U.S.-headquartered pharmaceutical and biotechnology organizations but also included some based in Europe, Canada or Asia. Even prior to the major HHS cuts in August, these stakeholders were feeling squeezed; nearly half reported "already experiencing direct impacts" from federal policy changes tied to mRNA funding.

The cuts caused projects to be scaled back, partnerships to be terminated, and jobs to be lost. About 30% of respondents said that, if faced with further cuts, they might pivot away from mRNA, and 30% said they'd consider moving their operations to other countries. Over 80% agreed that anti-mRNA policies would drive talent away from the U.S. and toward other locales.

Even as scientists contend with these big-picture problems on the national and international stage, skirmishes have also been unfolding at the state level. These battles primarily concern public access to mRNA vaccines but could potentially have broader ripple effects.

A bill still in committee in Iowa would make administering an mRNA vaccine in the state a misdemeanor with a fine of $500 for each shot given. Another bill in committee in South Carolina would prohibit the use of mRNA-based "gene therapies" in the state, but makes an exception for therapies for noninfectious diseases, such as cancer.

It may be that most bills of this ilk never become law and some, like the one raised in South Carolina and two dead bills in Texas, purposely make exceptions for certain uses of mRNA. However, others have been worded in ways that made it unclear whether any mRNA medicine is permissible. If any of such bills ultimately pass at the state level, that could sway where mRNA companies can manufacture products and run clinical trials, Coller said. So, while an exodus of expertise unfolds at a national level, we may see an echo of that at the state level.

The future of mRNA medicine in the U.S. rests on many "ifs," and the worst-case scenario may not come to pass. But in the face of staggering uncertainty, researchers in the field are starting to look for better bets.

"Let's not fool ourselves: mRNA is one of the three most important molecules in the body, with the other two being DNA and protein. It's the intermediary between them," Coller said. "When the federal government sends a message that mRNA-based medicine and research is not wanted, you're basically saying that there's a whole branch of science that is no longer welcome within the U.S."

Within weeks of the first cases of a "mysterious pneumonia-like illness" being reported in Wuhan, China, public health leaders were convening to assess the threat and shore up systems to mitigate the potential harm to come. This work started unfolding months before COVID-19 would be officially declared a pandemic.

Dr. Seth Berkley — a renowned infectious-disease epidemiologist and former CEO of Gavi, an international organization aimed at improving children's vaccine access — was one figure at the forefront of the effort to ensure future COVID-19 vaccines would be distributed to the world's poorest nations. In his new book "Fair Doses: An Insider's Story of the Pandemic and the Global Fight for Vaccine Equity" (University of California Press, 2025), Berkley recounts those pandemic-era efforts and reflects on what went right and what went wrong.

Live Science spoke with Berkley about the book and the lessons we should take forward into the world's next big outbreak — the emergence of which, Berkley argues, is a matter of "when," not "if."

Nicoletta Lanese: What was the impetus to write this book?

Dr. Seth Berkley: When the book was written, the real purpose of it was to capture the experience [of the pandemic], post-COVID and post-COVAX. COVAX [COVID-19 Vaccines Global Access] was an initiative we put together when we realized that this looked like it was going to become a more severe infection. In doing that, we had all kinds of problems, but in the end, we did do the fastest and largest rollout of vaccines in history. We ended up with 57% of people in the developing world, the poorest 92 countries, getting coverage with primary doses, versus 67% globally — so not perfect equity, but better than it had ever been done before.

What I was worried about is [that] people wouldn't capture the lessons learned, both good and bad. The book tries to explain what it took to get there, and also who were the good players, who were the bad players.

Now, since the book was written, the world has changed dramatically. I couldn't — I mean, I suppose I could have ripped the book up and started writing again. I didn't do that, but I did have a chance to say in the preface, and then later on at the end of the book, how much had changed, given the intense anti-vaccine attitudes that we're seeing right now in the U.S. government, particularly in the secretary of health and human services [HHS], Robert Kennedy Jr., who is a long-term vaccine skeptic and a conspiracy theorist on these things.

It's obviously quite concerning in regard to how that may affect Americans. But also it's important for Americans to understand that the vaccine work that's done in other countries also affects America, because the diseases we get come from both inside and outside.

NL: On that point, we've seen the U.S. withdraw support from initiatives that support vaccine equity globally. What are the potential impacts of that?

SB: So if we go back — I'll use a period of 50 years, for convenience — less than 5% of people in the world received even a single dose of vaccine. Not all the doses that were recommended — a single dose. And we've gone from that level up until vaccines, now, are the most widely distributed health intervention in the world. Along with that, we've seen a 70% reduction in vaccine-preventable disease deaths, and we've seen a more than 50% reduction in under-5 child mortality, directly as a result of this type of work.

So this is a really big deal. We've also seen control of many infectious diseases: the eradication of smallpox, the almost complete elimination of wild polio, the control of measles in many countries, etc. etc. Those are the successes. But the idea now is that we back away from this, when we have these infectious diseases that are still a risk — and as we've recently seen in the U.S., we've had some big measles outbreaks.

The U.S. actually had received the status of having eliminated endogenous measles infections, meaning that when new infections would occur, they had to come from outside. Now, the U.S. is at risk of losing that designation. This is why it's so important to think about it globally, because if we see many more measles infections occurring in other countries and given the movement of people, you're eventually going to see those cases in the United States if vaccine rates go down. And they are going down.

We've got a situation where people are discrediting experts and putting people in place who do not have expertise and have preconceived notions on vaccines. They say they're trying to increase trust, but I don't see how that increases trust. And we're now fractured in the U.S.; you've seen most recently this idea that states are coming together to put out their own recommendations. Professional societies are putting out recommendations, instead of having one definitive set. In the end, I don't think that helps with confidence.

NL: Do you feel these shifts in the U.S. stem from an amplification of an old problem we've had, or more from a brand-new issue?

SB: It's a little of both. Vaccine hesitancy has existed from the first vaccine, which was in the 1700s smallpox right after the original vaccine was shown to work. There were cartoons showing — because the vaccine was derived from cows — there were pictures of people with cow horns growing out of their heads and all kinds of things like that. So this is not a new problem.

What is new is having the intense politicization of this — the idea that one political party more than another political party has these beliefs and therefore acts on them, so there are different coverage slates for vaccines for different parties. And then finally, [there's] the fact that you've got government leaders that are pushing these conspiracy theories and discrediting institutions that have scientific professionals and mechanisms that have been set up to try to have the best science possible.

During COVID, we saw Russian bots and Chinese bots that were providing disinformation, and of course, this spread like wildfire. But also for the first time that I know of, we had the U.S. government, the Defense Department, putting out misinformation to try to discredit the Chinese vaccine. So this is a kind of warfare that's going on that has some terrible effects. … This is a completely different level of anti-vaccine engagement than we've ever seen before.

NL: You often hear the argument that, because vaccines have worked so well, people lack a fear of vaccine-preventable diseases. Do you see any validity to that?

SB: When you look at this new era of misinformation — as I said, there's always been vaccine misinformation. But the difference is, if you are in a country that has very high vaccination rates and therefore the diseases have virtually disappeared, it's very easy for a parent to say, "I don't want my kid to be injected with something. … I don't know anything about these diseases. I've never seen them. How bad can they be?" So that's one side of it.

When you're living in a developing country and these diseases are still there, you see kids that have morbidity from these diseases. You see people paralyzed from polio. You see people who are blind or deaf from German measles [also called rubella]. And so your benefit-harm ratio is seen as different in these different populations. And it's the job of science to ask the question, what is the benefit-to-cost ratio of these products?

The other thing that's really hard is, because we don't see these diseases, you don't know the kind of really severe side effects that occur. In measles, there's a disease called subacute sclerosing panencephalitis. It's a fairly rare disease — but when it happens, the child's brain dissolves, and there is nothing you can do.

The challenge is that you don't want people to live in fear all the time, but no parent wants that to happen to their child. It's about how you can both educate and have people aware of the side effects of these diseases, and even ones that are rare. That's really the challenge right now. I think the only way to solve that is education.

NL: Another focus of the book is a roadmap to global vaccine equity. What do you see as the biggest obstacles to that goal?

SB: First of all, the stuff we've just discussed, which is having awareness of the value of vaccination, and that's critical for populations everywhere in the world. And obviously keeping that knowledge up even when the diseases get rarer and rarer is really important.

The second critical point is having access to vaccines. What Gavi was able to do was, by consolidating the buying power of many different countries, we were able to drive the price [of routine vaccines] down 98% from that of what it cost in the United States, which makes it really affordable. Vaccines are cost-effective even at higher prices, but obviously the more affordable they are, the better it is. So a priority is making sure that those products are available and that they are being produced in the quantities they need.

The third part of it is having delivery systems in place, and this is really a challenge. As I mentioned at the beginning, vaccines are the most widely distributed health intervention, and about 90% of families in the world have access to routine vaccines. … Reaching [the last 10%] with that system not only provides vaccines but also provides health access, and it also means there is an early warning system to make sure that there are health workers for everybody — so that if there are outbreaks or weird diseases that appear, you have a system that can report back.

Lastly, I'd say that there's importance in having global surveillance for new infections. It's evolutionarily certain we're going to have new outbreaks and new pandemics, and that warning system is critical for everybody in the world. Building this prevention system, which is very cost-effective, is the right thing to do everywhere, and it's a matter of making that a priority.

NL: I want to come back to the point that epidemics and pandemics are essentially inevitable. With that in mind, how do we prepare?

SB: Epidemics are evolutionarily certain — certainly, that's true. So the first part of that is, how do we prepare for things that we know, like flu, like COVID, like hemorrhagic fevers? These are things that we now have interventions for. And how do we make sure that the world is ready, that there are systems of laboratories, that there are stockpiles of vaccines ready to go, and [that there's] the ability to scale them up?

Unfortunately, a lot of that is now being broken apart. At this moment in time, we [the United States] are firing people in major health agencies. We're pulling out of the World Health Organization. We're changing our development assistance and stopping training of scientists, etc. etc. So we are breaking down the systems that exist to deal with that [preparation for known threats], which is a real problem.

Then, when you get to the "unknown unknowns," you also want to have the science ready to go. There's a good example right now, of pulling out of mRNA vaccines. [The HHS recently pulled funding from research-and-development projects focused on mRNA vaccines.] mRNA vaccines may not be perfect; they may not even be the best vaccines for some diseases. But they are the fastest, because you can make them very quickly from the genome. Then you can, in essence, "print" the vaccine and scale it up very quickly.

In the case of a very severe pandemic that has a very high mortality rate, that is the best way: to make an mRNA vaccine to deal with it. The idea that we would not want to continue to work on mRNA — improving it, making it better — and instead we're just pulling research out seems to me to be very, very shortsighted indeed.

NL: To continue on mRNA, would you say that in a pandemic scenario, it's speed that's the most crucial element of the vaccine? Or are there other advantages to the mRNA platform?

SB: The absolute advantage there is speed. And remember, COVID had a mortality rate of about 1.5%, 2%. Some of the other diseases that we know of, that potentially could spread, have mortality rates of 20%, 30%, 40%, 50%. If you had something like that — that's a respiratory pathogen spreading quickly with very high mortality rates — every hour counts in terms of speed.

So mRNA is the fastest. … It may be that, once you have mRNA vaccines, you may want to shift to other vaccines that may give longer duration of protection, give better immune responses, etc. [for a given pathogen]. But you can't make those in the same time frame, so it may be a handoff from one to another.

One of the challenges in COVID was that there were over 200 different vaccines that were made, but mRNA was so fast out of the block that others really didn't get a chance to become successful. If I use an example, the Novavax vaccine, which is a protein[-based vaccine], never really got global traction, even though it was a very effective, very safe vaccine that maybe had a longer duration of protection.

The challenge is, how do we, in that setting, have comparative science to say which are the best products? That will not be done by the pharmaceutical sector because they don't have any incentive to do head-to-head comparisons. That needs to be done by international agencies or by governments.

NL: What else can readers expect from "Fair Doses"?

SB: The book is also filled with lots of interesting nuggets of stories of who behaved well and who didn't behave well during the pandemic, and that includes political leaders, that includes pharmaceutical companies, that includes agencies. So it gives a nuanced understanding of what that time really looked like.

We came together, along with our partners, to try to see if we could change the normal dynamic that occurs in a pandemic, which is wealthy countries buy all the doses and there's no doses available for anybody else. That was our goal going into it, and the book tells the story of how we put together this initiative, how we raised the $12.5 billion necessary to buy vaccines, how we ultimately delivered more than 2 billion doses to 146 countries.

One of the questions is, how do we do better? What do we learn from that? And that's something we try to explore in the book.

Editor's note: This interview has been lightly edited for length and clarity.

This article is for informational purposes only and is not meant to offer medical advice.

Months before COVID-19 was officially declared a pandemic, public health leaders were poring over the early data coming out of China and preparing for the worst.

Dr. Seth Berkley — a renowned infectious-disease epidemiologist and former CEO of Gavi, an international organization aimed at improving children's vaccine access — was among those leaders. In January 2020, Berkley and colleagues were working to establish an infrastructure so that, if and when scientists created vaccines for this novel virus, the shots wouldn't be hoarded by high-income countries and denied to poor nations.

Now, Berkley has released a new book — "Fair Doses: An Insider's Story of the Pandemic and the Global Fight for Vaccine Equity" (University of California Press, 2025) — that recounts how that initiative unfolded and what lessons were learned through the process, while underscoring why the broader fight for vaccine equity is far from finished.

On January 23, 2020, I was high up in the Swiss Alps in Davos, attending the World Economic Forum (WEF). I was at Davos as the CEO of Gavi, the Vaccine Alliance, the largest purchaser of vaccines in the world and which worked to provide new and underutilized vaccines to children in developing countries — countries in which about half the world's children live. As usual, I was preoccupied with how we could do a better job protecting the world with vaccines for new and old diseases. And there were murmurs of a new epidemic of respiratory disease caused by a novel coronavirus in China on the horizon.

At the bar of the Hard Rock Hotel my wife, Cynthia [an academic physician and consultant], and I met with Richard Hatchett, CEO of the Coalition for Epidemic Preparedness Innovations (CEPI). Over nachos and drinks, we started to talk through what was likely to happen with the new coronavirus, which would later be named COVID-19. Discussion about the disease hadn't really reached a high political level and was not formally on the Davos agenda, but concern was growing, and many people during that week asked us our opinions.

The first question we discussed was whether this was just going to be a worrisome outbreak or the Big One that epidemiologists had long warned might come. So far, we only had official confirmation of a point outbreak, spreading from animals at the Wuhan live animal market to humans. But on the nerdy LISTSERVs about infectious disease and epidemics, there was already a lot of chatter about how the virus might be spreading from person to person, which is a huge red flag in our field. We agreed that there was potential for the new virus to spread dramatically. Regardless of whether this was or was not the Big One, we needed to prepare.

Such a scenario creates a problem for all countries, even those with access to the vaccines. But to me a far bigger concern was the unfairness of high-income countries' self-interest. People in developing nations without access to vaccines were historically already the most vulnerable to disease and the most likely to suffer complications if they got sick. They already had limited access to the most basic medical treatment.

Improving the delivery of existing vaccines and building up better delivery systems is the best way to detect outbreaks early, prepare communities for outbreaks of disease, and ensure health systems aren't overwhelmed in an emergency — as well as strengthen our epidemic stockpiles.

If vaccines against the disease could be made — and at the time, we were far from certain they could be — we knew that stocks would be quickly bought up by the richest countries. The logical conclusion was that the bulk of the world's population, and most especially those in lower income, developing countries, would be locked out of these deals, and so denied timely access to whatever vaccine supplies became available.

That was where we thought we could help. So, Richard, Cynthia, and I talked through a rough outline of what would be needed to ensure equitable access to any COVID-19 vaccines that emerged and the roles that various organizations — such as CEPI, Gavi, UNICEF, and WHO — as well as the pharmaceutical companies might play to make that happen.

Imagining ourselves in the place of government decision-makers, we envisioned that they would have an incentive to participate in a mechanism that pooled risk by making advance purchase commitments for a wide variety of candidate vaccines. Their buy-in could help us pool demand, generating enough scale to incentivize increasing production and to negotiate the best prices on everyone's behalf. We wanted to promote solidarity, to publicize and meet lower-income country needs, and to create an early, strong global movement for equitable access.

Richard went from Davos back to London and talked with the CEPI team, I went back to Geneva to talk to the Gavi team and our Alliance partners WHO and UNICEF, and we started our collaboration. That joint effort became COVAX [COVID-19 Vaccines Global Access, an initiative to ensure equitable access to COVID-19 vaccines].

Our small team working on COVAX undertook what I believe was the most ambitious public health effort of the 21st century so far. The first COVAX dose was delivered to a COVAX-supported country 39 days after the first jab in the United Kingdom. Due to the time required for WHO to prequalify the vaccine, 43 days later the first doses were administered in Africa, in Ghana and Côte d'Ivoire. Forty-two days later, COVAX vaccines had been distributed to 100 countries. There were many delays due to export bans, vaccine nationalism, and manufacturing delays. But by the end of 2021, close to 1 billion doses had been distributed; by the end of 2022, COVAX had delivered more than 1.6 billion doses to people in the world's poorest countries and was estimated to have averted 2.7 million deaths in those countries. That's the fastest rollout of vaccines to developing countries ever.

WHO estimates that some 16 million people died during the first two years of the pandemic; we are still counting, and that number will doubtlessly grow. And COVID-19 is by no means the only infectious risk: Currently, about one in seven deaths, accounting for more than 7 million people a year, is due to an infectious disease. Millions of people die from diseases for which we already have vaccines.

It's hard to put numbers on the deaths that have been prevented by vaccines, but some estimates say that vaccines have saved more than half a billion lives over the past 70 years, the time period they have been routinely available. And this only covers the 30 or so vaccines we have against the more than 300 infectious diseases known to plague humanity.

More and better vaccines need to be developed, particularly for major killers such as tuberculosis, malaria, and HIV, and, hopefully, more cancers. And in the meantime, the risks for infectious diseases are shifting.

Even those of us who had been working in the field for years were surprised at how poorly prepared the world was for an emergency of this magnitude. What's more, we faced the perils of vaccine nationalism, vaccine diplomacy, and the sometimes-selfish behaviors of manufacturers and world leaders. It was clear from the start that we wouldn't be able to do this work perfectly. But we did our best, and I've sought to set down both what we did and what I wish we could have done differently so that we can learn from our history.

As the world continues to recover from the worst of the pandemic years, we may not relish thinking about another pandemic ahead. We face complacency, fatigue, and a growing distrust of both science and institutions, fed by intentional disinformation that spreads rapidly online. But we also have an opportunity to harness what we've learned to do better next time — and there is epidemiologic certainty that a next time will come. When it does, we need to have robust public health systems in place, and ideally, vaccines.

Reprinted from Fair Doses: An Insider's Story of the Pandemic and the Global Fight for Vaccine Equity by Seth Berkley, MD, courtesy of University of California Press. Copyright 2025.

The COVID-19 mRNA-based vaccines that saved 2.5 million lives globally during the pandemic could help spark the immune system to fight cancer. This is the surprising takeaway of a new study that we and our colleagues published in the journal Nature.

While developing mRNA vaccines for patients with brain tumors in 2016, our team, led by pediatric oncologist Elias Sayour, discovered that mRNA can train immune systems to kill tumors — even if the mRNA is not related to cancer.

Based on this finding, we hypothesized that mRNA vaccines designed to target the SARS-CoV-2 virus that causes COVID-19 might also have antitumor effects.

So we looked at clinical outcomes for more than 1,000 late-stage melanoma and lung cancer patients treated with a type of immunotherapy called immune checkpoint inhibitors. This treatment is a common approach doctors use to train the immune system to kill cancer. It does this by blocking a protein that tumor cells make to turn off immune cells, enabling the immune system to continue killing cancer.

Remarkably, patients who received either the Pfizer or Moderna mRNA-based COVID-19 vaccine within 100 days of starting immunotherapy were more than twice as likely to be alive after three years compared with those who didn't receive either vaccine. Surprisingly, patients with tumors that don't typically respond well to immunotherapy also saw very strong benefits, with nearly fivefold improvement in three-year overall survival. This link between improved survival and receiving a COVID-19 mRNA vaccine remained strong even after we controlled for factors like disease severity and co-occurring conditions.

To understand the underlying mechanism, we turned to animal models. We found that COVID-19 mRNA vaccines act like an alarm, triggering the body's immune system to recognize and kill tumor cells and overcome the cancer's ability to turn off immune cells. When combined, vaccines and immune checkpoint inhibitors coordinate to unleash the full power of the immune system to kill cancer cells.

Why it matters

Immunotherapy with immune checkpoint inhibitors has revolutionized cancer treatment over the past decade by producing cures in many patients who were previously considered incurable. However, these therapies are ineffective in patients with "cold" tumors that successfully evade immune detection.

Our findings suggest that mRNA vaccines may provide just the spark the immune system needs to turn these "cold" tumors "hot." If validated in our upcoming clinical trial, our hope is that this widely available, low-cost intervention could extend the benefits of immunotherapy to millions of patients who otherwise would not benefit from this therapy.

What other research is being done

Unlike vaccines for infectious diseases, which are used to prevent an infection, therapeutic cancer vaccines are used to help train the immune systems of cancer patients to better fight tumors.

We and many others are currently working hard to make personalized mRNA vaccines for patients with cancer. This involves taking a small sample of a patient's tumor and using machine learning algorithms to predict which proteins in the tumor would be the best targets for a vaccine. However, this approach can be costly and difficult to manufacture.

In contrast, COVID-19 mRNA vaccines do not need to be personalized, are already widely available at low or no cost around the globe, and could be administered at any time during a patient's treatment. Our findings that COVID-19 mRNA vaccines have substantial antitumor effects bring hope that they could help extend the anti-cancer benefits of mRNA vaccines to all.

What's next

In pursuit of this goal, we are preparing to test this treatment strategy in patients with a nationwide clinical trial in people with lung cancer. People receiving an immune checkpoint inhibitor will be randomized to either receive a COVID-19 mRNA vaccine during treatment or not.

This study will tell us whether COVID-19 mRNA vaccines should be included as part of the standard of care for patients receiving an immune checkpoint inhibitor. Ultimately, we hope that this approach will help many patients who are treated with immune therapy, and especially those who currently lack effective treatment options.

This work exemplifies how a tool born from a global pandemic may provide a new weapon against cancer and rapidly extend the benefits of existing treatments to millions of patients. By harnessing a familiar vaccine in a new way, we hope to extend the lifesaving benefits of immunotherapy to cancer patients who were previously left behind.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

The Centers for Disease Control and Prevention, long considered the nation's — if not the world's — premier public health organization, is mired in a crisis that not only threatens Americans' health but also its very survival as a leading public health institution.

The degree of this crisis was on full display during Health and Human Services Secretary Robert F. Kennedy Jr.'s Sept. 4, 2025, testimony before the U.S. Senate.

In the hearing, Kennedy openly criticized CDC professionals' response to the COVID-19 pandemic, saying "the people at CDC who oversaw that process, who put masks on our children, who closed our schools, are the people who will be leaving."

Kennedy's hearing came on the heels of a contentious week in which Kennedy fired the CDC's director, Susan Monarez, spurring 12 members of the Senate Finance Committee — including 11 Democrats and independent Bernie Sanders — to call on Kennedy to resign from his position.

At least four top CDC leaders resigned following Monarez's ouster, citing pressure from Kennedy to depart from recommendations based on sound scientific evidence.

I am a teaching professor and public health professional. Like many of my colleagues, the disruption happening at the CDC in recent months has left me scrambling to find alternate credible sources of health information and feeling deeply concerned for the future of public health.

The CDC's unraveling

These leadership shakeups come on the heels of months of targeted actions aimed at unraveling the CDC's structure, function and leadership as it has existed for decades.

The turmoil began almost as soon as President Donald Trump took office in January 2025, when his administration enacted sweeping cuts to the CDC's workforce that health experts broadly agree jeopardized its ability to respond to emerging health threats.

Trump used executive orders to limit CDC employees' communication with the public and other external agencies, like the World Health Organization.

Within weeks, he ordered as much as 10% of the overall workforce to be cut.

Soon after, Kennedy — who was newly appointed by Trump — began undoing long-standing CDC institutions, like the Advisory Committee on Immunization Practices, replacing all 17 of its members in a move that was widely denounced by health experts.

Critics pointed to a lack of qualifications for the new committee members, with more than half never having published research on vaccinations and many having predetermined hostility toward vaccines.

In June, more than 20 authoritative organizations, including the National Medical Association and American Academy of Pediatrics, expressed serious concerns for the health impacts of overhauling the advisory committee.

How Monarez's removal spurred the crisis

Public health leaders had cheered the July confirmation of Monarez as the CDC's new director, seeing her nomination as a welcome relief to those who value evidence-based practice in public health. Monarez is an accomplished scientist and career public servant.

Many viewed her as a potential voice of scientific wisdom amid untrained officials appointed by Trump, who has a track record of policies that undermine public health and science.

In her role as acting director, to which she was appointed in January, Monarez had quietly presided over the wave of cuts to the CDC workforce and other moves that drastically reshaped the agency and weakened the country's capacity to steward the nation's health.

Yet Monarez had "red lines" that she would not cross: She would not fire CDC leadership, and she would not endorse vaccine policies that ran contrary to scientifically supported recommendations.

According to Monarez, Kennedy asked her to do both in an Aug. 27 meeting. When she refused, he asked her to resign.

Her lawyers pushed back, arguing that only the president had the authority to remove her, stating: "When CDC Director Susan Monarez refused to rubber-stamp unscientific, reckless directives and fire dedicated health experts, she chose protecting the public over serving a political agenda. For that, she has been targeted."

Ultimately, the White House made her dismissal official later that evening.

An agency in turmoil

Further exemplifying and deepening the crisis at the agency, on Aug. 8, a gunman who had expressed anger over COVID-19 vaccinations opened fire on CDC headquarters, killing a police officer.

Many health workers attributed this directly to misinformation spread by Kennedy. The shooting amplified tensions and made tangible the sense of threat under which the CDC has been operating over the tumultuous months since Trump's second term began. One employee stated that "the CDC is crumbling."

Public health experts, including former CDC directors, are sounding the alarm, speaking out about the precariousness of the agency's position. Some are questioning whether the CDC can even survive.

A crisis of trust

Even before the most recent shock waves, Americans said they were losing trust and confidence in CDC guidance: In April, 44% of U.S. adults polled said that they will place less trust in CDC recommendations under the new leadership. This would undoubtedly undermine the U.S. response if the country faces another public health challenge requiring a rapid, coordinated response, like COVID-19.

In addition to installing new members on the vaccine advisory committee, Kennedy abruptly changed the recommendations for flu and COVID-19 vaccines without input from the CDC or the vaccine advisory committee, and contrary to data presented by CDC scientists.

Public health professionals and advocates are now warning the public that vaccine recommendations coming from the CDC's Advisory Committee on Immunization Practices may not be trustworthy. They point to the lack of credibility in the review process for the new committee, the fact that members have made statements contrary to scientific evidence in the past, and failure to apply an evidence-to-recommendations framework as compromising factors. Critics of the committee even describe a lack of basic understanding of the science behind vaccines.

Health impacts are being felt in real time, with health care providers reporting confusion among parents as a result of the conflicting vaccine recommendations. Now, those who want to be vaccinated are facing barriers to access, with major retailers placing new limits on vaccine access in the face of federal pressure. This as vaccination rates were already declining, largely due to misinformation.

The end result is an environment in which the credibility of the CDC is in question because people are unsure whether recommendations made in the CDC's name are coming from the science and scientists or from the politicians who are in charge.

Filling the gaps

Reputable organizations are working to fill the void created by the CDC's precariousness and the fact that recommendations are now being made based on political will, rather than scientific evidence.

The American Academy of Pediatrics and the American College of Gynecology have both released recommended vaccination schedules that, for the first time, diverge from CDC recommendations.

And medical organizations are discussing strategies that include giving more weight to their recommendations than the CDC's and creating pathways for clinicians to obtain vaccines directly from manufacturers. These measures would create workarounds to compensate for CDC leadership voids.

Some states, including California, Oregon, Washington and New Mexico, are establishing their own guidance regarding vaccinations. Public health scientists and physicians are attempting to preserve data and surveillance systems that the Trump administration has been removing. But independent organizations may not be able to sustain this work without federal funding.

What's at stake

As part of its crucial work in every facet of public health, the CDC oversees larger-scale operations, both nationally and globally, that cannot simply be handed off to states or individual organizations. Some public health responses — such as to infectious diseases and foodborne illnesses — must be coordinated at the national level in order to be effective, since health risks are shared across state borders.

In a health information space that is awash with misinformation, having accurate, reliable health statistics and evidence-based guidelines is essential for public health educators like me to know what information to share and how to design effective health programs. Doctors and other clinicians rely on disease tracking to know how best to approach treating patients presenting with infections. The COVID-19 pandemic made clear the importance of laboratory science, a unified emergency response and rapid distribution of effective vaccines to the public.

One of the strengths of the American system of governance is its ability to approach challenges — including public health — in a coordinated way, having a federal level of cooperation that unifies state-level efforts.

The CDC has been the nation's preeminent public health institution for more than eight decades as a result of its vast reach and unparalleled expertise. Right now, it's all sitting at a precarious edge.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Human papillomavirus (HPV) vaccines can dramatically reduce the rate of infections that cause cervical cancer, even in people who haven't been vaccinated, a new long-term study reveals.

Most cases of cervical cancer are caused by high-risk HPV viruses, which can drive changes in cells that turn them cancerous. Two types of high-risk HPV are most likely to cause cervical cancer. After the introduction of HPV vaccines in the U.S., the shots reduced the amount of people testing positive for those cervical-cancer-causing viruses by a whopping 98.4% in vaccinated teens and young women in Cincinnati, the focus of the new study. Meanwhile, in unvaccinated people of the same age, the rates of infection still fell by 71.6% in the same time period.

This demonstrates that HPV vaccines, introduced in the U.S. in 2006, can lead to herd immunity, which is when a population becomes so resistant to the spread of a virus that even unvaccinated people are indirectly protected.

HPV is the most common sexually transmitted infection worldwide; that stat includes both low- and high-risk strains. While it's primarily known for its potential to cause cervical cancer, exposure to high-risk HPV can also lead to other cancers in both sexes, according to a statement released by the researchers. These include those affecting the anus, head and neck.

Scientists have known for many years that HPV vaccines are highly effective, significantly reducing the rate of cervical precancers in young U.S. women and preventing cervical cancer deaths. However, the new 17-year study, published Monday (Sept. 29) in the journal JAMA Pediatrics, found that the vaccines have also reduced high-risk cervical infections in adolescent girls and young women at increased risk of HPV, even when they themselves were not vaccinated.

Nearly all sexually active people get HPV at some point in their lives. The infections are typically symptomless and tend to go away on their own within two years. However, in some cases, they can persist and ultimately cause cancers.

A 2020 study published in The Lancet Global Health estimated that in 2018, there were 690,000 cases of cancer attributed to HPV worldwide, including 620,000 in women and 70,000 in men. Cervical cancer accounted for about 80% of these cancer cases. So while most people don't get cancer as a result of an HPV infection, the virus' prevalence makes it a major public health problem.

In the new study, the researchers analyzed data from six surveillance studies in Cincinnati, collected from 2006 — the year before the vaccine became available there — to 2023. The study included 2,335 adolescent girls and young women between 13 and 26 years old. They focused primarily on participants who had an increased risk for HPV because they had multiple sexual partners or a history of sexually transmitted infection.

Multiple HPV vaccines have been introduced since 2006, and this study assessed the effectiveness of three versions: the 2-valent version, which guards against HPV 16 and HPV 18, the HPV responsible for more than 70% of cervical cancers; the 4-valent version, which additionally covers HPV 6 and HPV 11; and the 9-valent versions, which protect against another five types.

During the study period, the rate of HPV infections fell as the vaccines became available and the proportion of vaccinated participants increased, from 0% to 82%. Infections covered by the 2-valent vaccine dropped by 98.4% among vaccinated individuals, while the remaining HPV types covered by the 4-valent and 9-valent vaccines dropped by 94.2% and 75.7%, respectively.

The 9-valent vaccine was just as protective as the 2-valent and 4-valent vaccines in clinical trials, lead study author Dr. Jessica Kahn, a professor of pediatrics at the Albert Einstein College of Medicine in New York, told Live Science. But the decline in virus types targeted by the 9-valent vaccine was lower in this real-world scenario because it was licensed more recently, meaning fewer participants had received at least one dose of that version by the time of the study.

Among unvaccinated participants, HPV 16 and HPV 18 infections dropped by 71.6% in the study population, while the remaining two strains covered by the 4-valent vaccine dropped by 75.8%, indicating a high degree of herd immunity. The researchers didn't have enough data to effectively look at all the strains covered by the newer 9-valent vaccine in unvaccinated people.

The findings are good news for highly vaccinated areas, but rates of cervical cancer are higher in poorer countries than in the U.S. Globally, only 31% of adolescent girls and 8% of adolescent boys between 9 and 14 years old have received one dose of an HPV vaccine, according to 2024 World Health Organization data, the latest available. Increasing vaccine uptake worldwide could have dramatic impacts.

"By expanding uptake of this highly safe and effective vaccine, and ensuring access to screening and treatment, we can achieve one of the greatest public health victories of our time: the elimination of cervical cancer worldwide," Kahn said.

This article is for informational purposes only and is not meant to offer medical advice.

For almost 40 years, people who suspect they've been harmed by a vaccine have been able to turn to a little-known system called the Vaccine Injury Compensation Program — often simply called the vaccine court.

Health and Human Services Secretary Robert F. Kennedy Jr. has long been a critic of the vaccine court, calling it "biased" against compensating people, slow and unfair. He has said that he wants to "revolutionize" or "fix" this system.

I'm a scholar of law, health and medicine. I investigated the history, politics and debates about the Vaccine Injury Compensation Program in my book "Vaccine Court: The Law and Politics of Injury."

Although vaccines are extensively tested and monitored, and are both overwhelmingly safe for the vast majority of people and extremely cost-effective, some people will experience a harmful reaction to a vaccine. The vaccine court establishes a way to figure out who those people are and to provide justice to them.

Having studied the vaccine court for 15 years, I agree that it could use some fixing. But changing it dramatically will be difficult and potentially damaging to public health.

Deciphering vaccine injuries

The Vaccine Injury Compensation Program is essentially a process that enables doctors, lawyers, patients, parents and government officials to determine who deserves compensation for a legitimate vaccine injury.

It was established in 1986 by an act of Congress to solve a specific social problem: possible vaccine injuries to children from the whole-cell pertussis vaccine. That vaccine, which was discontinued in the U.S. in the 1990s, could cause alarming side effects like prolonged crying and convulsions. Parents sued vaccine manufacturers, and some stopped producing vaccines.

Congress was worried that lawsuits would collapse the country's vaccine supply, allowing diseases to make a comeback. The National Childhood Vaccine Injury Act of 1986 created the vaccine court process and shielded vaccine manufacturers from these lawsuits.

Here's how it works: A person who feels they have experienced a vaccine-related injury files a claim to be heard by a legal official called a special master in the U.S. Court of Federal Claims. The Health and Human Services secretary is named as the defendant and is represented by Department of Justice attorneys.

Doctors who work for HHS evaluate the medical records and make a recommendation about whether they think the vaccine caused the person's medical problem. Some agreed-upon vaccine injuries are listed for automatic compensation, while other outcomes that are scientifically contested go through a hearing to determine if the vaccine caused the problem.

Awards come from a trust fund, built up through a 75-cent excise tax on each dose of covered vaccine sold. Petitioners' attorneys who specialize in vaccine injury claims are paid by the trust fund, whether they win or lose.

Some updates are needed

Much has changed in the decades since Congress wrote the law, but Congress has not enacted updates to keep up.

For instance, the law supplies only eight special masters to hear all the cases, but the caseload has risen dramatically as more vaccines have been covered by the law. It set a damages cap of US$250,000 in 1986 but did not account for inflation. The statute of limitations for an injury is three years, but in my research, I found many people file too late and miss their chance.

When the law was written, it only covered vaccines recommended for children. In 2023, the program expanded to include vaccines for pregnant women. Vaccines just for adults, like shingles, are not covered. COVID-19 vaccine claims go to another system for emergency countermeasures vaccines that has been widely criticized. These vaccines could be added to the program, as lawyers who bring claims there have advocated.

These reform ideas are "friendly amendments" with bipartisan support. Kennedy has mentioned some of them, too.

A complex system is hard to revolutionize

Kennedy hasn't publicly stated enough details about his plan for the vaccine court to reveal the changes he intends to make. The first and least disruptive course of action would be to ask Congress to pass the bipartisan reforms noted above.

But some of his comments suggest he may seek to dismantle it, not fix it. None of his options are straightforward, however, and consequences are hard to predict.

Straight up changing the vaccine court's structure would probably be the most difficult path. It requires Congress to amend the 1986 law that set it up and President Donald Trump to sign the legislation. Passing the bill to dismantle it requires the same process. Either direction involves all the difficulties of getting a contentious bill through Congress. Even the "friendly amendments" are hard — a 2021 bill to fix the vaccine court was introduced but failed to advance.

However, there are several less direct possibilities.

Adding autism to the injuries list

Kennedy has long supported discredited claims about harms from vaccines, but the vaccine court has been a bulwark against claims that lack mainstream scientific support. For example, the vaccine court held a yearslong court process from 2002 to 2010 and found that autism was not a vaccine injury. The autism trials drew on 50 expert reports, 939 medical articles and 28 experts testifying on the record. The special masters deciding the cases found that none of the causation hypotheses put forward to connect autism and vaccines were reliable as medical or scientific theories.

Much of Kennedy's ire is directed at the special masters, who he claims "prioritize the solvency" of the system "over their duty to compensate victims." But the special masters do not work for him. Rather, they are appointed by a majority of the judges in the Court of Federal Claims for four-year terms — and those judges themselves have 15-year terms. Kennedy cannot legally remove any of them in the middle of their service to install new judges who share his views.

Given that, he may seek to put conditions like autism on the list of presumed vaccine injuries, in effect overturning the special masters' decisions. Revising the list of recognized injuries to add ones without medical evidence is within Kennedy's powers, but it would still be difficult. It requires a long administrative process with feedback from an advisory committee and the public. Such revisions have historically been controversial, and are usually linked to major scientific reviews of their validity.

Public health and medical groups are already mobilized against Kennedy's vaccine policy moves. If he failed to follow legally required procedures while adding new injuries to the list, he could be sued to stop the changes.

Targeting vaccine manufacturers

Kennedy could also lean on his newly reconstituted Advisory Committee on Immunization Practices to withdraw recommendations for certain vaccines, which would also remove them from eligibility in the vaccine compensation court. Lawsuits against manufacturers could then go straight to regular courts. On Aug. 14, 2025, the Department of Health and Human Services may have taken a step in this direction by announcing the revival of a childhood vaccine safety task force in response to a lawsuit by anti-vaccine activists.

Kennedy has also supported legislation that would allow claims currently heard in vaccine court to go to regular courts. These drastic reforms could essentially dismantle the vaccine court.

People claiming vaccine injuries could hope to win damages through personal injury lawsuits in the civil justice system instead of vaccine court, perhaps by convincing a jury or getting a settlement. These types of settlements were what prompted the creation of the vaccine court in the first place. But these lawsuits could be hard to win. There is a higher bar for scientific evidence in regular courts than in vaccine court, and plaintiffs would have to sue large corporations rather than file a government claim.

Raising the idea of reforming the vaccine court has provoked strong reactions across the many groups with a stake in the program. It is a complex system with multiple constituents, and Kennedy's approaches so far pull in different directions. The push to revolutionize it will test the strength of its complex design, but the vaccine court may yet hold up.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

At a Sept. 4, 2025, hearing before the Senate Finance Committee, Health and Human Services Secretary Robert F. Kennedy Jr. faced heated questions from numerous senators about his vaccine policies, including his stance on COVID-19 vaccines and mRNA vaccine technology generally.

Although Kennedy agreed that Operation Warp Speed, President Donald Trump's signature initiative to produce COVID-19 vaccines in nine months, was a tremendous achievement, he also maintained that COVID-19 vaccines cause widespread and serious harm, including death, particularly in young people — a claim for which there is no evidence.

Some especially pointed questions came from Republican Sen. Bill Cassidy of Louisiana, a physician who provided the final vote needed for Kennedy's confirmation in February 2025 after Kennedy promised him that he would not change the Centers for Disease Control and Prevention's process for recommending vaccines. Cassidy pointed out that with the limitations and confusion caused by the CDC's new rules around COVID-19 vaccines, "I would say effectively we are denying people vaccines." To which Kennedy replied, "Well, you're wrong."

At the hearing, Kennedy stood by his decision to cut US$500 million in HHS funding for 22 research contracts on mRNA vaccine technology. HHS has said it will instead pour these funds into research on a traditional approach to designing vaccines that was first used more than 200 years ago. With such vaccines, called whole-virus vaccines, a person's immune system is presented with the whole virus, often in weakened or inactivated form. This switcheroo has puzzled many scientists.

A few days before the hearing, on Sept. 1, Trump demanded that pharmaceutical companies prove that COVID-19 mRNA vaccines work, saying that the CDC was "being ripped apart over this question." It was his first public acknowledgment of the chaos roiling the CDC amid the firing of its director, Susan Monarez, and subsequent resignations of four high-level agency officials.

Meanwhile, public health experts and HHS staffers are calling for Kennedy to be fired, and several senators at the hearing echoed that call.

As a vaccinologist who has studied and developed vaccines for over 35 years, I see that the science behind mRNA vaccine technology is being widely misstated. This incorrect information is shaping long-term health policy in the U.S. — which makes it urgent to correct the record.

Are mRNA vaccines less safe than whole-virus vaccines?

HHS defended its cancellation of mRNA vaccine research based, in part, on a nonpeer-reviewed compilation of selected publications called the COVID-19 mRNA "vaccine" harms research collection. This document lists about 750 articles claimed to describe harms caused by mRNA vaccines against COVID-19. However, the vast majority of these articles aren't about vaccines but about the harms of getting infected with SARS-CoV-2, the virus that causes COVID-19. And notably absent from it is the huge body of data showing mRNA vaccines actually prevent these harms.

For example, the document being used to justify RFK Jr.'s claims about mRNA vaccines highlights 375 studies reporting that the virus's spike protein alone, which is produced when the virus replicates, can cause excessive inflammation and tissue damage. This is true. But the document marshals this evidence to support the claim that mRNA vaccines, which are designed to produce spike proteins, cause the same harm — which is not accurate.

While viral replication results in uncontrolled production of a large amounts of the protein, the way it's produced by the mRNA vaccine is very different. The vaccine produces a small, controlled amount of spike protein inside a few cells — just enough to induce an immune response without causing damage. And by blocking the virus's replication, it reduces the amount of spike protein in circulation, actually having the opposite effect.

What about side effects like myocarditis?

Early reports flagged a type of heart swelling called myocarditis as a rare side effect of the mRNA vaccine, particularly for young men ages 18 to 25 after a booster dose. A 2024 review identified about 20 cases out of 1 million people who received the vaccine. However, that same study found that unvaccinated people had an elevenfold higher risk of getting myocarditis after a COVID-19 infection than vaccinated people.

What's more, another 2024 study showed that people who developed myocarditis after vaccination had fewer complications than those who developed the condition after getting infected with COVID-19.

Do mRNA vaccines make the SARS-CoV-2 virus resistant?

Another claim from the compilation of supposed mRNA vaccine harms that was cited as a reason for cutting funding for mRNA technology is that mRNA vaccines cause mutations in the SARS-CoV-2 virus that make them resistant or less susceptible to the vaccine.

When a virus replicates in its host, it produces millions of copies of its genetic material. Mutations are copying errors that occur naturally during the replication process. These acquired mutations produce new variants, which is why both the COVID-19 mRNA and the whole-virus flu vaccine get updated annually — to keep up with natural changes in the virus.

Slowing down viral replication decreases the rate at which a virus can acquire new mutations. Since both mRNA and whole-virus vaccines stop or slow the virus from replicating, both types of vaccines help reduce the emergence of resistant viruses.

Viruses can mutate to escape from antibodies, but the mRNA vaccines are not causing the emergence of more virulent strains, likely for at least two reasons. First, mRNA vaccines induce immune responses that can attack the virus at multiple spots, so it would have to come up with many mutations at once to escape the vaccine's defenses. Second, even if the virus could acquire all these mutations, they would likely weaken it, making it unable to cause or even transmit disease.

mRNA vaccines versus new SARS-CoV-2 variants

Kennedy, in announcing cuts to mRNA vaccine research on Aug. 5, 2025, claimed that mRNA vaccines don't work against respiratory viruses and that HHS was moving toward "safer, broader vaccine platforms that remain effective even as viruses mutate."

Both whole-virus vaccines and mRNA vaccines protected against COVID-19 and prevented hospitalization and death for millions of people worldwide between 2020 and 2024, but there's clear evidence that the mRNA-based vaccines provided significantly better protection than whole-virus vaccines. And for COVID-19, mRNA vaccines are more effective against new variants, which emerge as viruses mutate, than whole-virus vaccines.

The COVID-19 mRNA vaccines started with exceptionally high efficacy, exceeding 94%. When the SARS-CoV-2 delta and omicron variants emerged in the spring and fall of 2021, mRNA vaccines became less effective in preventing infections. However, they remained highly effective in preventing severe illness, whereas in unvaccinated people the rates of severe illness and hospitalization remained high.

This is because mRNA vaccines induce the immune system to make both antibodies and specialized immune cells called T cells. These elements can recognize multiple parts of the virus, including ones that don't change, enabling significant protection against new variants.

What's more, the mRNA vaccines have a superpower that no other type of vaccine can currently match: They can be quickly updated and manufactured within two to three months. To develop a whole-virus vaccine, researchers must first spend months isolating and propagating the virus. Conversely, making an mRNA vaccine requires just sequencing the virus's genetic code — a process that today takes just hours.

If a new pandemic began today, mRNA vaccines are currently the only type of vaccine that could be developed quickly enough to disrupt its spread.

The future of mRNA vaccine technologies

Thirty years ago, when scientists first started developing mRNA vaccine technology, they recognized its potential to overcome major limitations of whole-virus vaccines — namely, slow production time and more limited ability to protect from new viral variants. Today, mRNA vaccines are also being developed to prevent or treat diseases including HIV and cancer, as well as autoimmune and genetic diseases.

Of course, this technology can be further improved. New mRNA vaccine technologies are aimed, among other things, at making mRNA vaccines easier to store to allow for faster distribution and reduce their short-term side effects, eliminate the rare risk of myocarditis and more quickly block a respiratory infection.

The National Institutes of Health is funneling money away from new mRNA technologies toward a single project developing universal vaccines based on traditional whole-virus vaccine technology. Universal vaccines are urgently needed to provide broader protection against ever-changing respiratory viruses, such as influenza, that are major pandemic threats.

A 2022 study in mice and ferrets showed that a universal flu vaccine NIH plans to support has promise. However, multiple studies of potential universal flu vaccines based on mRNA technology show even more potential. Such vaccines could induce broader immunity than whole-virus vaccines by eliciting antibody and T-cell responses that target an even wider range of flu viruses.

It's hard to square those benefits with the fact that HHS and NIH have named the planned new universal vaccine platform "Generation Gold Standard," insisting that it represents a new standard in science and transparency. The effort seems more akin to eliminating all e-bike technology and telling everyone who seeks one to get by with a single brand of a 10-speed bike: Getting to the intended destination may still be possible, but it will be slower and harder.

And in the case of abandoning mRNA vaccine research, it may lead to lives needlessly lost, whether due to potential medicines untapped or to pandemic unpreparedness.

This article was updated to include details from Kennedy's Sept. 4, 2025, hearing.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Over the past two centuries, vaccines have been critical for preventing infectious diseases. The World Health Organization estimates that vaccination prevents between 3 million and 5 million deaths annually from diseases like diphtheria, tetanus, influenza, measles and, more recently, COVID-19.

While there has long been broad scientific consensus that vaccines prevent or mitigate the spread of infections, there is new research suggesting that the therapeutic impact might go beyond the benefit of preventing infectious diseases.

An April 2025 study published in the prominent journal Nature found tantalizing evidence that the herpes zoster — or shingles — vaccine could lower the risk of dementia in the general population by as much as 20%.

We are a team of physician scientists with expertise in the clinical and basic science of neurodegenerative disorders and dementia.

We believe that this study potentially opens the door to other breakthroughs in understanding and treating dementia and other degenerative disorders of the brain.

A role for vaccines in reducing dementia risk?

One of the major challenges researchers face when trying to study the effects of vaccines is finding an unvaccinated "control group" for comparison — a group that is similar to the vaccine group in all respects, save for the fact that they haven't received the active vaccine. That's because it's unethical to assign some patients to the control group and deprive them of vaccine protection against a disease such as shingles.

The Nature study took advantage of a policy change in Wales that went into effect in 2013, stating that people born on or after September 2, 1933, were eligible for the herpes zoster vaccination for at least a year, while those born before that cutoff date were not. The vaccine was administered to prevent shingles, a painful condition caused by the same virus that causes chickenpox, which can lie dormant in the body and be reactivated later in life.

Related: Shingles vaccine may directly guard against dementia, study hints

The researchers used the policy change as a natural laboratory of sorts to study the effect of shingles vaccination on long-term health outcomes. In a statistically sophisticated analysis of health records, the team found that the vaccine reduced the probability of getting dementia by one-fifth over a seven-year period. This means that people who received the shingles vaccine were less likely to develop clinical dementia over the seven-year follow-up period, and women benefited more than men.

The study design allowed researchers to compare two groups without actively depriving any one group of access to vaccination. The two groups were also of comparable age and had similar medical comorbidities — meaning similar rates of other medical conditions such as diabetes or high blood pressure.

Results from this and other related studies raise the possibility that vaccines may have a broader role in experimental therapeutics outside the realm of infectious diseases.

These studies also raise provocative questions about how vaccines work and how our immune system can potentially prevent dementia.

How vaccines might be protective

One scientific explanation for the reduction of dementia by the herpes zoster vaccine could be the direct protection against the shingles virus, which may play a role in exacerbating dementia.

However, there is also the possibility that the vaccine may have conferred protection by activating the immune system and providing "trained immunity," in which the immune system is strengthened by repeated exposure to vaccines or viruses.

The study did not differentiate between different types of dementia, such as dementia due to Alzheimer's disease or dementia due to stroke. Additionally, researchers cannot draw any definitive conclusions about possible mechanisms for how the vaccines could be protective from an analysis of health records alone.

The next step would be a prospective, randomized, double-blind, placebo-controlled study — the "gold standard" for clinical trials in medicine — to directly examine how the herpes zoster vaccine compares with a placebo in their ability to reduce the risk of dementia over time. Such studies are necessary before any vaccines, as well as other potential therapies, can be recommended for routine clinical use in the prevention of dementia.

The challenges of untangling dementia

Dementia is a major noncommunicable disease that is a leading cause of death around the world.

A January 2025 study provided updated figures on lifetime dementia risk across different subsets of the U.S. population. The researchers estimate that the lifetime risk of dementia after age 55 is 42% — more than double earlier estimates. The dementia risk was 4% by age 75, and 20% by age 85, with the majority of risk occurring after 85. The researchers projected that the number of new cases of dementia in the U.S. would double over the next four decades from approximately 514,000 cases in 2020 to 1 million in 2060.

Once considered a disease largely confined to the developed world, the deleterious effects of dementia are now apparent throughout the globe, as life expectancy increases in many formerly developing countries. While there are different forms of dementia with varying clinical manifestations and underlying neurobiology, Alzheimer's disease is the most common.

Prospective studies that specifically test how giving a vaccine changes the risk for future dementia may benefit from studying patient populations with specific types of dementia because each version of dementia might require distinct treatments.

Unfortunately, for the past two to three decades, the amyloid hypothesis of Alzheimer's disease — which posits that accumulation of a protein called amyloid in the brain contributes to the disorder — dominated the scientific conversation. As a result, most of the efforts in the experimental therapeutics of Alzheimer's disease have focused on drugs that lower the levels of amyloid in the brain.

However, results to date have been modest and disappointing. The two recently approved amyloid-lowering therapies have only a minimal impact on slowing the decline, are expensive and have potentially serious side effects. And no drug currently approved by the Food and Drug Administration for clinical use reverses the cognitive decline.

Studies based on health records suggest that past exposure to viruses increase the risk of dementia, while routine vaccines, including those against tetanus, diphtheria, pertussis, pneumonia, shingles and others, reduce the risk.

Innovation and an open mind

There is sometimes a tendency among scientists to cling to older, familiar models of disease and a reluctance to move in more unconventional directions.

Yet the process of doing science has a way of teaching researchers like us humility, opening our minds to new information, learning from our mistakes and going where that data takes us in our quest for effective, lifesaving therapies.

Vaccines may be one of those paths less traveled. It is an exciting possibility that may open the door to other breakthroughs in understanding and treating degenerative disorders of the brain.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

It's August, and parents and caregivers are frantically preparing their kids for a new school year by buying supplies, filling out forms and meeting teachers. This year, many parents also face a question that's more complicated than usual: Should my child get an updated COVID-19 vaccine, and will I even have that choice? For some, that decision may have already been made by chaotic federal policy, just as COVID-19 cases are rising nationwide.

As a pediatrician and researcher who studies vaccine delivery and health policy, I am hearing uncertainty from both parents and health care providers. If that describes you, you are not alone. A poll published Aug. 1, 2025, by the health policy organization KFF found half of parents are unsure whether federal health agencies are recommending COVID-19 vaccines for healthy children this fall.

The process that normally provides clear, consistent recommendations and ensures availability for vaccines before respiratory virus season has been upended, and this year's COVID-19 vaccine guidance for children is a prime example.

How the process typically works

For over two decades, there was a predictable, well-coordinated process to ensure recommended seasonal vaccines, such as the flu shot, were available for anyone who wanted them by early fall. In recent years, COVID-19 vaccines have been incorporated into this same annual cycle.

Beginning in February, the Food and Drug Administration, including its independent committee of experts, reviewed data and approved the optimal formulation. After FDA approval, the Advisory Committee on Immunization Practices, or ACIP, an independent panel of experts that advises the Centers for Disease Control and Prevention, reviewed the evidence in public meetings and issued clear recommendations.

The U.S. has long followed an established set of steps lining up vaccines for any given year.

Manufacturers then scaled up production; insurers confirmed coverage, which is tied to the advisory committee's recommendations; and doses were distributed nationwide so vaccines would be available in clinics and pharmacies before the leaves started turning. This usual series of steps ensured that guidance incorporated input from scientists, epidemiologists, public health experts, clinicians, manufacturers, insurers and consumers. It also fostered trust among health care providers and, in turn, provided parents with clarity and confidence when making decisions.

Related: 'These decisions were completely reckless': Funding cuts to mRNA vaccines will make America more vulnerable to pandemics

What's different this year

Since Robert F. Kennedy Jr. took over as secretary of Health and Human Services in February 2025, that usual, tightly choreographed dance has become a chaotic scramble marked by uncertainty and a lack of transparency. Decisions about vaccine guidance have been made through internal channels without the same level of public discussion, review of the evidence or broad stakeholder input.

In May 2025, Kennedy and FDA leadership bypassed the agency's independent review committee and announced that some COVID-19 vaccines would be approved only for children with high-risk conditions. One formulation has yet to be FDA-approved for children at all. The secretary first announced updated recommendations for children on X, stating COVID-19 vaccines would no longer be recommended for healthy children. Shortly after, the CDC posted guidelines that differed from that announcement and said healthy children "may" receive them. Meanwhile, the Advisory Committee on Immunization Practices was disbanded by Kennedy and replaced with a smaller, hand-picked panel that operates with less transparency and has yet to weigh in on COVID-19 vaccines for children.

Public messaging has added to the confusion. Statements from newly appointed federal health leaders have questioned the safety of COVID-19 vaccines and the long-standing processes for ensuring their safety. Funding for mRNA technology, which supports several COVID-19 vaccines and is being explored for use against other diseases and even some cancers, has been cut. And many of the claims used to justify these actions have been challenged by experts as inaccurate or misleading.

What this means for parents

For parents, the result is uncertainty about whether their children should be vaccinated, when and where the vaccines will be available, whether insurance will cover them, or whether their choice has effectively been made for them by newly appointed health leaders operating outside the guardrails of the normal vetting process. This uncertainty comes at a time when the uptake of COVID-19 vaccines in children is already lower than that of other routine vaccines.

Currently, CDC guidelines say healthy children six months and older "may" receive a COVID-19 vaccine based on shared decision-making with their health care provider. The CDC recommends that children who are moderately or severely immunocompromised receive it. These guidelines differ from FDA approvals and Kennedy's guidelines announced on X, and they have not been reviewed or voted on in an advisory committee on immunization practices meeting.

Parents can start by talking with their child's pediatrician about benefits and potential risks, confirming eligibility and checking on insurance coverage. Pediatricians welcome parents' questions and work tirelessly to provide answers grounded in the best available evidence so families can make truly informed decisions about their child's health.

In some cases, unfortunately, even if parents want the vaccine and their pediatrician agrees, they may not be able to get it due to any number of factors, including local supply shortages, lack of insurance coverage, policies that prevent administration by pharmacists and other health providers without clear federal guidance, or an unwillingness of providers to give it "off-label," meaning in a way that differs from the FDA's official approval. For those parents, their decision has been made for them.

Reducing risks in other ways

Whether or not a child receives an updated COVID-19 vaccine, parents can still take steps to reduce illness, including keeping children home when sick, teaching them cough-and-sneeze hygiene and encouraging frequent hand-washing. The CDC provides national and state data on seasonal respiratory illnesses, including COVID-19, while local public health websites often offer community-level information.

Parents should also remember that the COVID-19 vaccine is not the only thing to consider before school starts. Routine immunizations such as those for measles, mumps and rubella, known as the MMR vaccine; diphtheria, tetanus and pertussis, called DTaP; and influenza are essential for keeping kids healthy and in school. These are widely available for now. This is particularly important, as this year the United States has experienced the highest number of measles cases in decades.

Uncertainty surrounding COVID-19 vaccine recommendations, and potentially other vaccines, may worsen in the coming weeks and months. It is possible parents will continue to see shifting guidance, conflicting statements from federal agencies and reduced access to vaccines in their communities.

In this chaotic environment, parents can look to trusted sources such as their pediatrician or organizations such as the American Academy of Pediatrics, which will continue to provide independent, evidence-based vaccine guidance.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Cells use mRNA to build proteins, and after years of research, scientists learned how to harness this molecule to develop effective, safe and quick-to-make vaccines. Since the advent of this Nobel Prize-winning technology, a handful of mRNA vaccines have been approved in the United States — namely, COVID-19 and RSV shots. Vaccines still in development could someday protect against seasonal flu, bird flu, HIV and more.

But now, the U.S. federal government is slashing its investments in mRNA vaccines — a move that will immediately impact 22 projects totaling nearly $500 million, the U.S. Department of Health and Human Services (HHS) announced Tuesday (Aug. 5).

Some projects in late stages will be allowed to wrap up, but "no new mRNA-based projects will be initiated," the statement said. The department will also cease "all mRNA-based equity investments" coordinated through its partner Global Health Investment Corp., a nonprofit that supports the development of public health technologies through venture capital.

Robert F. Kennedy Jr., HHS secretary and founder of the anti-vaccine group Children's Health Defense, claimed in the statement that mRNA vaccines "fail to protect effectively against upper respiratory infections" and said that the HHS will shift to funding "safer, broader vaccine platforms." These alternatives are later defined as whole-virus vaccines and unspecified "novel" technologies.

Per the statement, this retreat from mRNA vaccines will not impact "other uses of mRNA technology." But "I can tell you that the industry doesn't trust that," said Jeff Coller, the Bloomberg distinguished professor of RNA biology and therapeutics at Johns Hopkins University, who has studied mRNA for more than 30 years. "Even though the cancellation was specific to infectious disease, it really was a shot across the bow to the entire industry."

mRNA is useful for more than combating infectious diseases. It could potentially be applied as a cancer therapy, a vehicle to deliver gene-editing treatments into the body, a way to rein in autoimmune diseases like multiple sclerosis, or a treatment for the dangerous pregnancy disorder preeclampsia, for example.

Live Science spoke with Coller about the recent funding cuts and their anticipated impacts on the mRNA field and health of Americans.

Related: What are mRNA vaccines, and how do they work?

Nicoletta Lanese: Can you talk about how the HHS stance on mRNA vaccines had been shifting prior to Tuesday's cuts?

Jeff Coller: It was clear early on, before Robert F. Kennedy was nominated for the position of secretary of HHS, that he was, first of all, a vaccine skeptic, and highly critical of mRNA-based vaccines, as well. His statements before his appointment included some things like, "The mRNA vaccines were some of the most dangerous medicines introduced into the human population."

[After his appointment], one of the first things that he did was to dissolve the committee that oversees the procedures of vaccinations within the United States called ACIP [Advisory Committee on Immunization Practices], and he appointed new individuals to that committee. One of those includes an individual who is an mRNA skeptic: Robert Malone, who has claimed on TV and Joe Rogan that mRNAs are dangerous.

In addition to that, in about March of this year, there was an internal memo sent to NIH [National Institutes of Health] employees, asking them to disclose if they were working on mRNA vaccines, as well as to disclose who their colleagues were. This was made public and was published in journals like Science and was a warning sign that they were potentially going to target individuals associated with this type of research.

So we are already starting to feel that there was a growing anti-mRNA sentiment within the HHS, and then the cancellation of Moderna's bird flu contract that happened about maybe six weeks ago was probably the first direct action of an mRNA program being canceled by the federal government. And now, what happened two days ago [was that] funding was canceled for 22 of these mRNA projects that were investigating various vaccines.

NL: Are you aware of the specifics of any of those projects?

JC: We do know of some clinical trials that were already underway [and were impacted], and this included influenza — which is, of course, the big one — as well as respiratory syncytial virus, or RSV; cytomegalovirus, which is often called CMV; Zika, Epstein-Barr virus; and hepatitis B.

NL: The HHS statement drew a line between mRNA vaccines and "other uses" of mRNA. Do you think that those other projects will be unaffected?

JC: Well, I can tell you that the industry doesn't trust that. And the reason why I know that is that I'm one of the founders of the Alliance for mRNA Medicines. This is an organization of over 75+ members, many are biotech — small biotech, large biopharma, as well as major academic medical centers, including [Johns] Hopkins and Penn [the University of Pennsylvania] and the Mayo Clinic. We did a survey very early in the [Trump] administration to ask about some of these policy changes that were coming down from HHS. The overwhelming response from our membership was that they felt that the United States was becoming an unfriendly place for mRNA-based technology.

Even though the cancellation was specific to infectious disease, it really was a shot across the bow to the entire industry. It sent a chilling effect through the industry that basically makes everyone question, should we continue to invest in these programs within the United States?

The arguments that were made [by RFK Jr.] were vague and are not based on what is accepted in the scientific community. In fact, most of his statements are false. So, given that that decision was clearly made on nonscientific beliefs, then the industry is going to be scratching their head and thinking, "Well, maybe we should probably look elsewhere to develop our products, other countries."

NL: One example I was thinking about was "cancer vaccines," which are more of an immunotherapy. Do you think HHS will carve out an exception for those?

JC: We don't know. And we've tried to move away from using the word "cancer vaccine" on purpose. We started referring to them as "cancer neoantigen therapies." To start thinking about you changing your wordage because you're worried about how the administration is going to perceive what it is you're doing is alarming.

Many of these technologies that are being developed for cancer are still very early in research and development. These are still not even in the biotech space; a lot of them are still in the academic setting. If you're an academic lab, are you really going to continue down this road if you are not going to be able to get funding? I personally know of investigators that are doing clinical trials on mRNA-based approaches for cancer who are scared — they're actually scared to talk to reporters like you. They're scared to even mention that they have mRNA-based medicines, because their patients will suffer if the funding gets cut off.

NL: Another example I was thinking of was gene editing, and specifically CRISPR-based treatments. How could those be affected?

JC: When CRISPR was discovered, gene editing had a huge promise of being able to cure rare genetic disorders. But the limitation of gene editing was that if you introduce a gene editor, you have to be able to stop it. You have to be able to go and correct the mutation, and then you have to stop that machinery from working because you don't want it to overdo its job. If it does so, it's going to continue to edit and edit and edit the genome, and then you have a problem.

What has now made gene editing possible in a human patient is mRNA. In the case of baby KJ [the first-ever recipient of a customized CRISPR treatment], the CRISPR technology was introduced as an mRNA. That is the critical feature that was necessary to get this to work. The beauty of the human body is that it makes mRNA and then it clears the mRNA; it gets it out. So by introducing the gene-editing technology as an mRNA, we could go in, get an effect for a very short period of time, and then let the body do what it normally does and get rid of it. So that was perfect to do on this little baby.

By undermining mRNA-based work, we're potentially limiting the ability to do this true personalized medicine approach of gene editing that could save millions of people's lives every year.

NL: How do you anticipate this divestment could affect pandemic preparedness in the U.S.?

JC: I actually think that these decisions were completely reckless in that regard and put America in significant harm's way, in terms of our national defense.

Through Donald Trump's leadership under Operation Warp Speed, we were able to identify a pathogen, have a sequence, make a possible vaccine, develop that in nine months, and deploy it to the American people in the next three months. That's unparalleled in human history. The reason why we're able to do that is because of the power of the mRNA platform, that it is so easy to develop and easy to produce at scale, and then easy to deploy to the greater population.

Traditional vaccines, meaning before the advent of mRNA vaccines, typically take between three to five years to develop. And you don't even know if it will be efficacious. If you have a pandemic, you do need a technology that can be rapidly deployed. Not continuing to investigate the usage of a technology that has proven itself is completely reckless and puts America and Americans in harm's way.

And the truth is that other countries recognize the power of mRNA vaccines and mRNA medicines and are doubling down on their investment — especially China. Quite frankly, if a pandemic comes out, we're going to be caught asking China for their vaccines.

NL: Do you think this could also prompt "vaccine tourism," in which Americans go abroad to get vaccinated?

JC: If there's a pandemic, like what might happen with avian flu, and we're not prepared, absolutely — if Canada has a vaccine, people are going to migrate north.

And you have to think about it even more broadly than that. The study that came from [Memorial] Sloan Kettering [Cancer Center] that showed such good efficacy on pancreatic cancer — if that research stops, and continues in Europe or in China and you're diagnosed with pancreatic cancer, you're going to go there. Right? So you can think about the different types of tourism outside of vaccine tourism, sort of medical tourism.

Related: 'Any protein you can imagine, it can deliver': AI will help discover the next breakthrough in RNA, says Nobel Prize winner Dr. Drew Weissman

NL: From an industry standpoint, what could these cuts mean for mRNA developers?

JC: First of all, you have other countries that are trying to recruit American companies to their shores through incentives. And they're trying to do the same with scientists through easy pathways to citizenship and grant and funding mechanisms. In addition to moving their brick-and-mortar operations overseas, these American companies will start developing drugs that are specific to other countries. There are viruses that are more resident in South America; the market in the United States just doesn't make sense, but we could easily sell those drugs to Brazil, for example.

That's what I think will happen in the short course. These companies will start making drugs and marketing them to other countries. But then, in the long term, they actually will move brick and mortar.

NL: Are there other impacts that you anticipate these cuts having?

JC: I think that this will certainly impact America's leadership in biomedical discovery. We're going to lose an entire generation of scientists through these types of actions.

Let's not fool ourselves: mRNA is one of the three most important molecules in the body, with the other two being DNA and protein. It's the intermediary between them. When the federal government sends a message that mRNA-based medicine and research is not wanted, you're basically saying that there's a whole branch of science that is no longer welcome within the U.S.

So if you're a young individual thinking about going to graduate school and becoming a scientist to try and use your talents to improve human health, you may not do that. You may not do that in the United States, at least. So I think the United States is going to fall dramatically behind in its leadership in biotech.

We're going to see, over the next five to 10 years, a significant brain drain, where other countries build up their infrastructure, and new scientists are not trained in the United States, and preexisting scientists flee.

NL: What's something you hope the public understands about these funding cuts and mRNA?

JC: I think that most Americans don't understand that mRNA is a natural substance, a natural part of your body. Every cell in your body has mRNA — thousands of copies of mRNA.

With mRNA-based medicines, we're not doing something that is dangerous or reckless. What we're doing as medical professionals is we're actually taking advantage of a natural system that exists within your body and using your body to help itself. It's really quite remarkable that we're able to do this. All we are doing is taking advantage of that remarkable system that preexists.

This article is for informational purposes only and is not meant to offer medical advice.

Scientists have developed a new, needle-free way to deliver vaccines: through the gumline.

In a new proof-of-concept study, researchers successfully vaccinated mice against influenza by cleaning their teeth with dental floss coated with inactive flu viruses.

Most vaccines are administered using a needle, an approach that has its drawbacks. For example, apprehension about pain from the injection and needle phobias can deter people from getting vaccinated. Additionally, injections require more medical expertise to administer than needle-free options, like mouth drops or nasal sprays, and are more challenging to store and distribute.

But a floss-based vaccine could eliminate the pain and logistical challenges surrounding injections and "even be distributed through the postal mail," the researchers behind the development wrote in their study, published July 22 in the journal Nature Biomedical Engineering.

Such a vaccine could potentially be deployed in "resource-limited settings with minimal training," they added, and be especially helpful in active outbreaks when vaccine coverage needs to be boosted quickly.

Previous studies have shown that vaccinations delivered in the cheek or under the tongue trigger satisfactory immune responses. But it can be difficult to deliver adequate doses of these vaccines through mucosal tissues in the mouth — the lining that acts as a barrier between our body and the environment.

Related: Acne vaccine: Experimental shot for common skin condition reaches clinical trials. Here's what you need to know.

The researchers behind the vaccine floss found a creative solution: Researchers focusing on gum disease have found particular areas in the mouth that are very permeable, meaning molecules are easily absorbed by the tissue. One of these areas is called the junctional epithelium (JE). The JE is found on the tissue between teeth, at the spot where the tooth's surface meets the gum line. By secreting different molecules, the JE detects and defends against pathogens that try to get in through the gums.

The study researchers thought that the JE's ability to allow molecules through and to stimulate an immune response made it a potential candidate for a vaccine site. To reach it, they needed something that could get into that small crevice between tooth and gum. So, they went out and bought some dental floss.

To explore this concept, the researchers tested their hypothesis in mice. Once they'd figured out how to floss a mouse's teeth — turns out, it's a two-person job — they set up a flossing schedule to expose 50 mice to an inactive flu virus. Killed, or "inactivated" viruses cannot cause infection and are a common component of vaccines; they're used to immunize humans against diseases such as hepatitis A and polio, for example, and are found in some types of flu shot.

One group of mice had their teeth flossed with the virus-coated floss three times, with two weeks between each dose. Then, a month after their final dose, they were exposed to an active flu virus. All survived, while a comparison group of mice that was left unvaccinated all died.

Further testing found that the mice that had been vaccinated via the floss had a strong immune response, producing ample antibodies and many immune cells. This immune defense was found throughout the body — known as systemic immunity — and in their saliva and feces.

"The floss-based vaccination induced both systemic and mucosal immunity, while conventional intramuscular shots largely stimulate systemic immunity," first study author Rohan Ingrole, a chemical engineer at Texas Tech University, told Live Science in an email. "Mucosal immunity is important because most of the pathogens enter through the mucosal routes," he emphasized.

In theory, vaccine floss could thus have an edge over syringe vaccines by triggering this additional protection, but the team would like to directly compare the two methods in the future to validate this idea.

Next, the researchers wanted to know if flossing could transfer compounds to the JE in humans. As an early test, they used a fluorescent marker and blue food coloring to coat a dental pick and had healthy volunteers floss their teeth with it. Photographs confirmed that a fair amount of the dye was transferred to the space between their teeth and gum, though just over 41% was left on the floss.

The next step, the researchers said, is to translate the research to larger animals, which "can then lay the foundation for human testing in the near future," senior study author Harvinder Gill, a bioengineer at North Carolina State University, told Live Science in an email.

This article is for informational purposes only and is not meant to offer medical advice.

Editor's note: This story doesn't reflect more recent developments from the Advisory Committee on Immunization Practices, which has now recommended against using flu vaccines containing thimerosal. Experts, including a lone member of the committee, have questioned the decision given the lack of risk posed by the preservative.

An expert committee that advises the Centers for Disease Control and Prevention on vaccines is meeting for the first time since Health Secretary Robert F. Kennedy Jr. abruptly replaced the committee's 17 members with eight hand-picked ones on June 11, 2025.

The committee, called the Advisory Committee on Immunization Practices, generally discusses and votes on recommendations for specific vaccines. For this meeting, taking place June 25-26, 2025, vaccines for COVID-19, human papillomavirus, influenza and other infectious diseases were on the schedule. According to an updated agenda, however, the committee is now also scheduled to hear a presentation on a chemical called thimerosal and to vote on proposed recommendations regarding its use in influenza vaccines.

Public health experts have raised concerns about the presentation, noting that anti-vaccine advocates continue to promote confusion regarding the purported health risks of thimerosal despite extensive research demonstrating its safety.

I'm a pharmacist and expert on drug information with 35 years of experience critically evaluating the safety and effectiveness of medications in clinical trials. No evidence supports the idea that thimerosal, used as a preservative in vaccines, is unsafe or carries any health risks.

What is thimerosal?

Thimerosal, also known as thiomersal, is a preservative that has been used in some drug products since the 1930s because it prevents contamination by killing microbes and preventing their growth.

In the human body, thimerosal is metabolized, or changed, to ethylmercury, an organic derivative of mercury. Studies in infants have shown that ethylmercury is quickly eliminated from the blood.

Ethylmercury is sometimes confused with methylmercury. Methylmercury is known to be toxic and is associated with many negative effects on brain development even at low exposure. Environmental researchers identified the neurotoxic effects of mercury in children in the 1970s, primarily resulting from exposure to methylmercury in fish. In the 1990s, the Environmental Protection Agency and the Food and Drug Administration established limits for maximum recommended exposure to methylmercury, especially for children, pregnant women and women of childbearing age.

Related: 'Vaccine rejection is as old as vaccines themselves': Science historian Thomas Levenson on the history of germ theory and its deniers

Why is thimerosal controversial?

Fears about the safety of thimerosal in vaccines spread for two reasons.

First, in 1998, a now discredited report was published in a major medical journal called The Lancet. In it, a British doctor named Andrew Wakefield described eight children who developed autism after receiving the MMR vaccine, which protects against measles, mumps and rubella. However, the patients were not compared with a control group that was vaccinated, so it was impossible to draw conclusions about the vaccine's effects. Also, the data report was later found to be falsified. And the MMR vaccine that children received in that report never contained thimerosal.

Second, the federal guidelines on exposure limits for the toxic substance methylmercury came out about the same time as the Wakefield study's publication. During that period, autism was becoming more widely recognized as a developmental condition, and its rates of diagnosis were rising. People who believed Wakefield's results conflated methylmercury and ethylmercury and promoted the unfounded idea that ethylmercury in vaccines from thimerosal were driving the rising rates of autism.

The Wakefield study was retracted in 2010, and Wakefield was found guilty of dishonesty and flouting ethics protocols by the U.K. General Medical Council, as well as stripped of his medical license. Subsequent studies have not shown a relationship between the MMR vaccine and autism, but despite the absence of evidence, the idea took hold and has proven difficult to dislodge.

Have scientists tested whether thimerosal is safe?

No unbiased research to date has identified toxicity caused by ethylmercury in vaccines or a link between the substance and autism or other developmental concerns — and not from lack of looking.

A 1999 review conducted by the Food and Drug Administration in response to federal guidelines on limiting mercury exposure found no evidence of harm from thimerosal as a vaccine preservative other than rare allergic reactions. Even so, as a precautionary measure in response to concerns about exposure to mercury in infants, the American Academy of Pediatrics and the U.S. Public Health Service issued a joint statement in 1999 recommending removal of thimerosal from vaccines.

At that time, just one childhood vaccine was available only in a version that contained thimerosal as an ingredient. This was a vaccine called DTP, for diphtheria, tetanus and pertussis. Other childhood vaccines were either available only in formulations without thimerosal or could be obtained in versions that did not contain it.

By 2001, U.S. manufacturers had removed thimerosal from almost all vaccines — and from all vaccines in the childhood vaccination schedule.

In 2004, the U.S. Institute of Medicine Immunization Safety Review Committee reviewed over 200 scientific studies and concluded there is no causal relationship between thimerosal-containing vaccines and autism. Additional well-conducted studies reviewed independently by the CDC and by the FDA did not find a link between thimerosal-containing vaccines and autism or neuropsychological delays.

How is thimerosal used today?

In the U.S., most vaccines are now available in single-dose vials or syringes. Thimerosal is found only in multidose vials that are used to supply vaccines for large-scale immunization efforts — specifically, in a small number of influenza vaccines. It is not added to modern childhood vaccines, and people who get a flu vaccine can avoid it by requesting a vaccine supplied in a single-dose vial or syringe.

Thimerosal is still used in vaccines in some other countries to ensure continued availability of necessary vaccines. The World Health Organization continues to affirm that there is no evidence of toxicity in infants, children or adults exposed to thimerosal-containing vaccines.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

On March 20, 2025, members of the World Health Organization adopted the world's first pandemic agreement, following three years of "intensive negotiations launched by governments in response to the devastating impacts of the COVID-19 pandemic." The U.S., however, did not participate, in part because of its intention to withdraw from the WHO.

Global health experts are hailing the agreement as a historic moment.

What does the agreement mean for the world, and how can it make everyone safer and more prepared for the next pandemic?

The Conversation asked Nicole Hassoun, a professor at Binghamton University and executive director of Global Health Impact, to explain the pandemic accord, its prospects for advancing global health, and the significance of the U.S.'s absence from it.

What more should be done, and does the U.S. have a role to play?

In my view, the best way to protect public health moving forward is for countries to sign on to the agreement and devote more resources to global health initiatives. This is particularly important given declining investment and participation in the WHO and the contraction of other international health initiatives, such as USAID.

Without international coordination, it will become harder to catch and address problems early enough to prevent epidemics from becoming pandemics.

It will also be imperative for member countries to provide funding to support the agreement's goals and secure the innovation and access to new technologies. This requires building the basic health infrastructure to ensure shots can get into people's arms.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Whooping cough, a bacterial infection that can be especially dangerous for babies and young children, is on the rise. Already in 2025 the U.S. has recorded 8,485 cases. That's compared with 4,266 cases during the same period in 2024.

Like measles, which is also spreading at unprecedented levels, whooping cough, more formally known as pertussis, can be prevented by a safe and effective vaccine. But with anti-vaccine sentiment increasing and cuts to immunization services, vaccination rates for whooping cough over the past two years have declined in children.

The Conversation asked epidemiologist Annette Regan to explain why pertussis has become so prevalent and how families can protect themselves from the disease.

What is pertussis and why is it dangerous?

Pertussis is a vaccine-preventable disease caused by the bacterium Bordetella pertussis. Researchers in France first identified the B. pertussis bacterium in 1906. The first recorded epidemic of pertussis is thought to have occurred in Paris in 1578.

Infection can cause an acute respiratory illness characterized by severe and spasmodic coughing spells. The classic symptom of pertussis is a "whoop" sound caused by someone trying to breath during a bad cough. Severe complications of pertussis include slowed or stopped breathing, pneumonia and seizures. The disease is most severe in young babies, although severe cases and deaths can also occur in older children and adults.

Some doctors call pertussis "the 100-day cough" because symptoms can linger for weeks or even months.

Related: Whooping cough outbreaks: Why is pertussis on the rise in several countries?

The World Health Organization estimates that 24.1 million pertussis cases and 160,700 deaths occur worldwide in children under 5 each year. Pertussis is highly contagious. Upon exposure, 80% of people who have not been previously exposed to the bacterium or vaccinated against the disease will develop an infection.

Fortunately, the disease is largely preventable with a safe and effective vaccine, which was first licensed in the U.S. in 1914.

How do cases last year and this year compare with past years?

During the COVID-19 pandemic between 2020 and 2022, pertussis cases were lower than usual. This may have been a result of limited social contact due to social distancing, masking, school closures and lockdown measures, which reduced the spread of disease overall.

In the past two years, however, pertussis cases have surpassed figures from before the pandemic. In 2024, local and state public health agencies reported 35,435 pertussis cases to the Centers for Disease Control and Prevention — a rate five times higher than the 7,063 cases reported in 2023 and nearly double the 18,617 cases reported in 2019 prior to the pandemic.

Between October 2024 and April 2025, at least four people in the U.S. have died of pertussis: two infants, one school-age child and one adult.

Why are pertussis cases rising?

Although vaccines have resulted in a dramatic decline in pertussis infections in the U.S., incidence of the disease has been rising since the 1990s, except for a brief dip during the COVID-19 pandemic.

Before the start of routine childhood vaccination for pertussis in 1947, its rates hovered between 100,000 and 200,000 cases per year. With vaccines, rates plunged under 50,000 annually by the late 1950s and under 10,000 per year in the late 1960s. They reached a low of 1,010 cases in 1976.

Starting in the 1980s and 1990s, however, the U.S. and several other countries have been seeing a steady resurgence of pertussis cases, which have exceeded 10,000 cases in the U.S. every year from 2003 to 2019. They dropped again during the pandemic until last year's resurgence.

There is no single explanation for why cases have been rising recently, but several factors probably contribute. First, pertussis naturally occurs in cyclic epidemics, peaking every two to five years. It is possible that the U.S. is headed into one of these peaks after a period of low activity between 2020 and 2022. However, some scientists have noted that the increase in cases is larger than what would be expected during a usual peak.

Some scientists have noted that this apparent resurgence correlates with a change in the type of vaccine used in children. Until the 1990s, the pertussis vaccine contained whole, killed B. pertussis bacteria cells. Whole-cell vaccine can stimulate a long-lasting immune response, but it is also more likely to cause fever and other vaccine reactions in children.

In the 1990s, national vaccine programs began to transition to a vaccine that contains purified components of the bacterial cell but not the whole cell. Some scientists now believe that although this partial-cell vaccine is less likely to cause high fevers in children, it provides protection for a shorter time. Immunity after whole-cell vaccination is thought to last 10-12 years compared with three to five years after the partial-cell vaccine. This means people may become susceptible to infection more quickly after vaccination.

Vaccination rates are also not as high as they should be and have started falling in children since 2020. In the U.S., the percent of kindergartners who are up to date with recommended pertussis vaccines has declined from 95% during the 2019-20 school year to 92% in the 2023-24 school year. Even fewer adolescents receive a booster dose.

How can people protect themselves and their families?

Routine vaccination for children starting in infancy followed by booster doses in adolescents and adults can help keep immunity high.

Public health experts recommend that children receive five doses of the pertussis vaccine. According to the recommendations, they should receive the first three doses at 2, 4 and 6 months of age, then two additional doses at 15 months and 4 years of age, with the aim of providing protection through early adolescence.

Infants younger than 6 weeks are not old enough to get a pertussis vaccine but are at the greatest risk of severe illness from pertussis. Vaccination during pregnancy can offer protection from birth due to antibodies that pass from the mother to the developing fetus. Many countries, including the U.S., now recommend that women receive one dose of pertussis vaccine between the 27th and 36th week of every pregnancy to protect their babies.

To maintain protection against pertussis after childhood, a booster dose of pertussis vaccine is recommended for adolescents at 11 to 12 years of age. The CDC recommends that all adults receive at least one booster dose.

Because immunity declines over time, people who are in contact with infants and other high-risk groups, such as caregivers, parents and grandparents, may benefit from additional booster doses. When feasible, the CDC also recommends a booster dose for adults 65 years and older.

Vaccine safety studies over the past 80 years have proven the pertussis vaccine to be safe. Around 20% to 40% of vaccinated infants experience local reactions, such as pain, redness and swelling at the vaccination site, and 3% to 5% of vaccinated infants experience a low-grade fever. More severe reactions are much less common and occur in fewer than 1% of vaccinated infants.

The vaccine is also highly effective: For the first year after receiving all five doses of the pertussis vaccine, 98% of children are protected from pertussis. Five years after the fifth dose, 65% of vaccinated children remain protected.

Booster vaccination during adolescence protects 74% of teens against pertussis, and booster vaccination during pregnancy protects 91% to 94% of immunized babies against hospitalization due to pertussis.

Families can talk to their regular health care providers about whether a pertussis vaccine is needed for their child, themselves or other family members.

This edited article is republished from The Conversation under a Creative Commons license. Read the original article.

Germ theory is the idea that pathogens can invade the human body and cause disease — and it wasn't always accepted. Evidence for germ theory accumulated over time, and as it did, it butted against existing explanations of how and why illnesses manifest. Yet now the theory is central to our understanding of why many diseases occur, as well as to how they can be prevented and cured.

In a new book, Thomas Levenson, a professor of science writing at MIT, traces the history of germ theory while tackling the broader question of why some ideas take hold and become accepted while others are ignored. The book — called "So Very Small: How Humans Discovered the Microcosmos, Defeated Germs — and May Still Lose the War Against Infectious Disease" (Random House, 2025) — brings the reader all the way to the present day, as humanity's struggles with germs continue in the form of antibiotic resistance and a new flavor of anti-vaccine sentiment.

Live Science spoke with Levenson about his new book, how germ theory came to be, and how its central dogma still faces denialists today.

Related: 'How could it have been allowed to happen?': The threat of 'superbugs' was known from the first antibiotic, but we've failed to stop it.

Nicoletta Lanese: When you're looking at the history of how germ theory emerged, were there competing ideas about disease that were particularly difficult to unseat?

Thomas Levenson: It was 200 years, almost to the day, between the discovery of microbes and the first definitive demonstration that microbes are the agents of infectious disease, which was Robert Koch's anthrax stuff. I said, "Why did it take so long?"

One of the problems germ theory had was that the prevailing theory was not terrible. It adequately described events in a plausible way. Towards the end of the pre-germ theory period, it even provided the framework for doing some things that were genuinely helpful. The whole hygiene movement comes out of the idea that something about noxious, decaying matter is bad for you.

By the 19th century, you're well past the time when the understanding of disease is that "it's God's punishment," or what have you — that the agency through which God imposed an illness would be through some kind of corruption, or miasma [the belief that disease spread through noxious air].

Even without the divine judgment side of things, the idea that corruption and decay could be carried from place to place on the air — that allowed you to understand how epidemics work, or contagion across some distance. Contagion formally means touching, but it evolved to sort of mean something that could be passed from one victim to another. And it accounted for a great deal … so miasma theory wasn't entirely unproductive. There wasn't an urgent, you know, "Nothing makes sense here. We need to think about this in a new way." There was never that kind of moment.

NL: It sounds like they understood the broader conditions that fostered germs but not that germs were the causative element.

TL: And I think that's because they already had a causative element. One of the themes throughout the book is this notion of hierarchies and the perception of one's place in them being really important.

[For example], living in bad conditions is bad. Even without God directly involved, there's still a strong moral argument, [because the idea was that] the poor are poor because they are bad. "Look at how they drink, look at the squalor in which they live, etcetera, etcetera." So disease is seen as the result of, in some sense, broader environmental and social decisions. Some people will say, "Well, you know, it's not the poor's fault that they're poor. It is the conditions in which they live that makes them vulnerable to disease, but those conditions are things we should fix."

And others said, "No, they live in those conditions because that's who they are." But either way, wherever you fall on that particular argument, the two sides agree on the underlying causation: crappy conditions, you get sick. And again, it's not entirely wrong; it's just not causally correct.

NL: In the book, you talk about there initially being resistance to the idea of handwashing. Could you sum that up?

TL: The great experiment to show that handwashing could stop an infectious disease in its tracks is the famous experiment by [Ignác] Semmelweis in Vienna, where he was in charge of two birthing wards — one entirely staffed by midwives, and the other which is entirely staffed by male doctors and medical students. He saw hugely different death rates: Midwives did much better than the doctors in preserving their patients from puerperal fever, which we now know is a bacterial infection.

Very often, the male doctors and students go directly from an autopsy to a birthing room, and he [Semmelweis] said, "I don't know what it is, but there's something on their hands that they're carrying from the corpse." They call them "corpse particles," and when spread to the living patients, that produces this terrible outcome, this terrible disease.

He says, "We've got to put something in between the autopsy room and the birthing room," and his solution was to … require them to use a chlorine solution, [which we now know to be] a really strong antiseptic. He said, "You have to scrub until you can no longer smell the corpse on your hands." And that was enough.

[However], it wasn't accepted, in part because he was not a very good medical communicator, and in part because the implications of what he had done was to say that doctors have been killing their patients for decades. What Semmelweis showed [in the 1840s] is that this terrible scourge, this epidemic of puerperal fever that had swamped Europe and the U.S., was caused by doctors not being clean enough. That's a very socially charged thing to say.

NL: Was there some pivotal moment that later changed the view of handwashing?

TL: The big changes start to happen in the years immediately after the American Civil War [when many soldiers died of infected battle wounds]. Probably the most important thing to change the idea of hospital and medical cleanliness was Joseph Lister's work on sterile surgery. It wasn't just women who were dying under the care of their gynecologists; surgery was an enormously hazardous practice really until the 1860s and 1870s.

Before there was anesthesia, you need to do operations really, really quickly, and there aren't that many things that you can do. You can amputate. You can drill holes in the skull to relieve pressure when it's there. You can try to operate for gallstones or kidney stones, though that often ended in infection and death. There was essentially no abdominal surgery.

Lister is one of the first to realize that the issue is microbes, and he does this because a friend of his, who's a chemist, tells him about Louis Pasteur's early work on microbes spoiling beer and wine. This was done in the 1860s, and news got to Scotland, where Lister was training. He said, "Aha, maybe the reason these surgical sites are getting infected every time is because these microbes that are all around us in the air, and they're getting into the wound and doing damage."

He worked out this very caustic approach: You close the wound up with a carbolic-acid-soaked bandage. And it worked. … Later, he performed the first antiseptic operation, on a kid who had a compound fracture, and was able to save the leg and save the child. Eventually, you get to aseptic, where, rather than try and kill the bacteria in the site, you try and keep the bacteria from getting there. And that's when you get things like washing hands [around the 1870s].

Related: Superbugs are on the rise. How can we prevent antibiotics from becoming obsolete?

NL: You don't focus only on the history of germ theory in the book but also issues of the present day, including rising antibiotic resistance. How well do you think it's being addressed?

TL: Antibiotic resistance scares the bodily fluid of your choice out of me. The good news is, I think that the antibiotic resistance problem is one that is fairly well understood; there aren't a lot of people who dissent from it. It's not like vaccines, where there's a real opposition to vaccines in themselves. Nobody is upset about the use of antibiotics, that I know of.

There's sort of at least two major things you need to do: You need to support a lot of research, some of which is not necessarily immediately beneficial. There's promising work being done — for example, on bacteriophages. These are viruses that infect bacteria that, at the turn of the 20th century, were a very, actively pursued idea [for treating bacterial infections]. That's coming back, and people are working on it.

Related: Dangerous 'superbugs' are a growing threat, and antibiotics can't stop their rise. What can?

Then, there is the search for more and different types of antibiotics, finding compounds that can interfere with bacterial metabolism in ways that so far they haven't experienced. There's a lot of science to be done there — which means we have to pay, which is not really what's happening in the United States right now. The reverse is happening; we're reining in our commitments to both basic, curiosity-driven science and the biomedical applications of it.

The other thing to do, of course, is to control the use of the antibiotics we have and that may be developed in the near future. That involves things like reducing the use of antibiotics in animal feed, trying to be much more careful about prescribing antibiotics, especially for viral illnesses, for which they will do no good, and so on — just reducing the amount of evolutionary challenge we put in front of bacteria so that we can slow the process of resistance.

But that requires collective action, and right now, we [the U.S.] are worse at it than we may have been. So that's problematic.

NL: Moving to the topic of vaccines, with the anti-vaccine sentiment we're seeing now, do you think we've been there before? Or is this somewhat unprecedented?

TL: Kind of both.

Vaccine hesitancy, vaccine resistance, vaccine rejection is as old as — and, in some senses, older than — vaccines themselves. Prior to true vaccines, you had people vigorously denouncing the idea of smallpox inoculation [in which healthy people were exposed to fluids from infected people's smallpox sores]. This is before you get to the cowpox vaccine; this is in the 1720s. [People said] "it violates God's will; it's unnatural; it's hazardous; it's all kinds of terrible things." And some of what they said was true … It was not a risk-free operation.

You get similar reactions to the first true vaccine against cowpox [which was used to confer smallpox immunity] that starts to get disseminated in 1798. There was almost immediately vaccine resistance, again seizing in part on the unnaturalness of it. "You're mixing stuff from a cow into a human body" — that's almost obscene to people. There are these great cartoons from that era, which show cow parts showing up on babies and so on.

As you go forward through time, there are rejections of vaccines as unnecessary. There are rejections of vaccines on spiritual grounds, in regards to their "unnaturalness." There are rejections of vaccines as an intolerable extension of state power into personal decision making. Once you start having compulsory vaccination laws, which is in the middle of the 19th century, people respond by saying, "No, you can't do that. You can't make me put this stuff in my body."

We saw that all over the COVID vaccines, and we're seeing it now with growing resistance to standard childhood-disease vaccines as a requirement. And the results are tragic and disastrous: There's that kid who died in Texas, and there's at least one other death in the measles outbreak that is likely caused by lack of vaccination. [Editor's note: At the time of publication, the second measles death has been confirmed, along with a third.]

I see this both as a continuation of the way people have always responded to vaccines, but you're also seeing stuff that I think is particular to our moment that's new. Twenty years ago, anti-vaccine sentiment was not really a marker of political identification; to be anti-vaccine was not to be clearly coded as associated with one political outlook or another. That's much less true now. I don't need to sugarcoat it; obviously when a Republican president appoints RFK Jr. as secretary of health and human services, the association of that stance with that wing of American politics is pretty strong.

I think the big risk now is that anti-vaccine sentiment will become a yet more partisan issue, and a lot of people are going to associate with anti-vaccine stuff without really engaging with the details of the argument or … the consequences of disease. That's a really difficult thing to counter.

There's no actual scientific or medical or material case that stands to scrutiny that says vaccines are bad — they're very good. They're the greatest lifesaving invention, enabler of human flourishing, perhaps ever. Infectious disease used to be the leading cause of death for human beings everywhere. It ain't no more. And it ain't no more in large part because of vaccines.

Editor's note: This interview was conducted on March 27, 2025. It has been lightly edited for clarity and length.

Editor's note: This story was first published on March 26, 2025.

We could see up to 10.8 million more HIV cases than anticipated in the next five years if planned cuts to international HIV funding take place.

This surge in infections in low- and middle-income countries would contribute up to 2.9 million more HIV-related deaths by 2030.

These disturbing figures come from a new modeling study published March 26 in the journal The Lancet HIV. The researchers wanted to analyze the potential impact of cuts to international funding for HIV/AIDS programs, which work to prevent both transmission and deaths related to the infection.

As of February 2025, the five top donors of this funding — the United States, United Kingdom, France, Germany and the Netherlands — have all announced significant cuts to foreign aid that threaten HIV programs worldwide. The study predicts how these cuts would impact low- and middle-income countries (LMICs), which since 2015 have relied on international sources for 40% of their HIV program funding.

"These findings are a sobering reminder that progress in the fight against HIV is not guaranteed — it is the result of sustained political will and investment," said Dr. Ali Zumla, a professor of infectious diseases and international health at University College London who was not involved in the research.

But equally, "the projected surge in new infections and deaths is not an inevitability; it is a consequence of choices being made today," Zumla told Live Science in an email. "If these funding cuts move forward, we risk unraveling decades of hard-won progress, leaving millions vulnerable and pushing global HIV goals further out of reach."

Related: We could end the AIDS epidemic in less than a decade. Here's how.

Unprecedented cuts to aid

As of 2023, five donors have supplied more than 90% of the international funding for HIV programs, with the United States providing over 72% of the total. Specific populations at high risk of HIV — including people who inject drugs, men who have sex with men, female sex workers and their clients, and transgender and gender diverse people — particularly rely on these international funding sources for access to HIV prevention and testing.

Much of the U.S. funding comes from the President's Emergency Plan for AIDS Relief (PEPFAR), which is largely implemented by the Agency for International Development (USAID). However, PEPFAR and USAID were hit by an unprecedented funding pause and staffing reduction in January, following an executive order from President Donald Trump.

PEPFAR later received a temporary waiver to continue some services, including those for antiretroviral therapy (ART), the drugs that keep HIV from progressing to AIDS. These treatments must be taken consistently or the virus will rebound.

"The widespread rollout and uptake of antiretroviral therapy funded by international sources has been one of the most important factors reducing AIDS related deaths in lower income settings," said Justin Parkhurst, an associate professor of global health policy at the London School of Economics and Political Science who was not involved in the study. ART also cuts the number of new infections by suppressing the virus in people living with HIV, thus preventing transmission, he told Live Science in an email.

However, despite the waiver, PEPFAR's services still haven't resumed as normal, given the waiver didn't trigger immediate funding to eligible programs and many clinics had already shuttered by the time it was issued. Even now, PEPFAR's future after the waiver's expiration remains uncertain.

Following the U.S., the next top four donors for international HIV funding are the U.K., France, Germany and the Netherlands. However, as of February 2025, each of these donors has also announced major cuts in foreign aid spending — "and more might follow," the study authors wrote.

Based on the projected cuts being made by the top five donors, the researchers used a mathematical model to predict the rates of new HIV cases and deaths. They focused their model on 26 LMICs, which together receive 49% of international HIV aid, overall, and 54% of PEPFAR aid. They then used the data from these 26 countries to extrapolate to all LMICs worldwide.

Cuts could "undo nearly all progress achieved since 2000"

The researchers considered several scenarios in their model. The first — the "status quo" — served as a baseline, projecting the rates of cases and deaths if recent levels of HIV spending were maintained between 2025 and 2030, rather than cut. In this scenario, more than 1.8 million new infections and over 720,000 HIV-related deaths occurred in LMICs.

In the worst-case scenario the team considered, all PEPFAR funding was indefinitely stopped on Jan. 20, 2025, and no alternative funding sources emerged to fill that gap. Simultaneously, other, non-PEPFAR sources of international funding were also reduced. That scenario led to an estimated 10.8 million more cases and 2.9 million more deaths than the status quo.

Related: Single-shot HIV treatment suppresses virus 10,000-fold for months, animal study finds

This suggests that "the number of new infections in 2026 could return to 2010 levels, and by 2030 the number of new infections could surpass historical estimates," the study authors wrote. "In the worst-case scenario, if PEPFAR funding were ceased entirely and no equivalent mechanism replaced it, surges in HIV incidence could potentially undo nearly all progress achieved since 2000."

This worst-case scenario would hit sub-Saharan Africa (SSA) particularly hard — out of eight SSA countries included in the analysis, six receive over 40% of their HIV funding through PEPFAR. Children in the region could see a nearly three-fold increase in HIV infections, the authors predicted.

And outside of SSA, other vulnerable populations, such as sex workers, would be much harder hit by such cuts than the general population, showing up to a six-fold higher increase in cases than other demographics, the data suggested.

The team also looked at a less extreme scenario, modeling what would happen if new funding sources filled the gap left by PEPFAR. In this scenario, they assumed that the gap could be partially filled by 2026 and then fully filled by 2027. If that mitigation were to happen, the number of extra cases drops to 4.4 million and the extra deaths to 770,000 over the course of five years.

So while filling the gap left by PEPFAR would help substantially, that sudden loss of funding would still have devastating impacts, the study suggests.

"Modelling reveals the potential for severe consequences following abrupt stopping, with no notice, of international support aimed at stopping AIDS as a global public health threat," Dr. Catherine Hankins, a professor of global and public health at McGill University in Canada who was not involved in the study, told Live Science in an email.

Cuts could be felt for decades to come

According to the study authors, even if the PEPFAR gap could be filled within two years, the ripple effects would be felt for decades to come. They estimated that it would take 20 to 30 extra years of 2024-level funding to end AIDS as a public health threat.

Ambitious goals set by UNAIDS have aimed to end the threat by 2030. And historic HIV trends suggested that many of the LMICs featured in the new paper could have hit their targets by about 2036, if funding continued at past levels, the authors wrote.

"This study indicates that an abrupt termination of programmes has serious risks to human life," Parkhurst said. "Even for those who believe the US or other governments should reduce foreign aid spending in this area, there can be planning around how to do so without producing serious harm to millions of people around the world who have come to rely on the treatment."

The study suggests that, if that abrupt stop could be avoided, many lives could be spared.

The researchers looked at what would happen if PEPFAR was reinstated or "equivalently recovered" and estimated that there could be 70,000 to 1.73 million extra cases and 5,000 to 61,000 extra deaths, compared to status quo. Those estimates assume that other international funding will still be reduced, but that countries will be able to make up for some of the lost funds domestically.

The new study has some limitations, as "there is inherent uncertainty in global modelling," said study co-first author Rowan Martin-Hughes, a senior research officer at the Burnet Institute in Australia.

The "most important" limitation is that there is uncertainty in the HIV fiscal space, although the authors covered some of that unpredictability by looking at a range of possible outcomes, Martin-Hughes told Live Science in an email. There are also gaps in the global reporting of financial data that could affect their model, and the 26 featured countries might not be fully representative of the overall impacts of funding cuts, he added.

However, "overall, we think most sources of uncertainty are likely to result in underestimating rather than overestimating the real effects of immediate and severe funding cuts to HIV programmes globally, especially in the sub-Saharan African region," he said.

In light of the impending cuts, "it is paramount now to track AIDS mortality and HIV incidence while urgently reversing the cuts, mitigating the effects, and creating new funding strategies to prevent further suffering," Hankins said.

Martin-Hughes agreed.

"Governments, donors, and stakeholders must collaborate on feasible mitigation strategies to preserve HIV prevention, testing, and treatment services to avoid a resurgence in the HIV epidemic," he said. "In doing so, the global community can secure both the immediate and long-term stability of resilient health systems so integral to saving lives through HIV epidemic control."

Global investment, especially from the U.S., has put targets for the elimination of HIV transmission within reach, he said. "But all of that progress is vulnerable, and could be wiped out within a few years if there are dramatic and unmanaged cuts to HIV services."

Many people first learned about mRNA vaccines during the coronavirus pandemic, when the companies Pfizer-BioNTech and Moderna released their COVID-19 vaccines. The Pfizer-BioNTech shot was the first COVID-19 vaccine to earn emergency authorization in the United States, and later, it would become the first mRNA vaccine of any kind to be fully approved by the U.S. Food and Drug Administration (FDA).

But even though these firsts took place during the pandemic, mRNA vaccines had been in development for many years before COVID-19 emerged as a threat.

Looking forward, they'll likely continue to play a big role in preventing — and even treating — other diseases in the future.

So what, exactly, are mRNA vaccines, and how do they work?

The future of mRNA vaccines

Although mRNA vaccines rose to prominence during the coronavirus pandemic, their applications stretch far beyond infectious diseases.

Today, many cutting-edge research groups are exploring the potential of mRNA technologies to treat conditions such as Celiac disease, lung damage, preeclampsia, brain cancer and pancreatic cancer.

"We are very excited about the application of mRNA vaccines to treat cancer," Balachandran said. "In our work on cancer vaccines, we use mRNA technology because it is amenable to rapid and flexible production, allowing us to customize a vaccine for every patient." Cancer vaccines generally work like a kind of immunotherapy, priming the immune system to go after tumor cells that can otherwise hide from its attacks.

Editor's note: Live Science spoke to Melissa Dibble prior to recent layoffs at the CDC, which the communications department was impacted by. This story was also updated after publication to note the mResvia shot as an additional example of an FDA-approved mRNA vaccine.

This article is for informational purposes only and is not meant to offer medical advice.

The current measles outbreak in the U.S. may last a full year, a public health official in Texas recently warned.

As of April 4, nearly 610 measles infections have sickened people across 22 jurisdictions in the U.S. this year, according to the Centers for Disease Control and Prevention (CDC). That's more than double the total number of measles cases reported for the whole of 2024. What's more, additional cases have been reported by various local jurisdictions but have yet to be confirmed by the CDC and added to its official count.

So far, 12% of the CDC-confirmed cases have led to hospitalization, and in February, an unvaccinated, school-age child in Texas died of the infection, making them the first person to die of measles in the U.S. since 2015. Another death was reported in New Mexico, again in an unvaccinated individual, and the case is being investigated by officials to confirm its connection to the outbreak. And in April, a second school-age child in Texas died of measles complications, local authorities reported.

Most of the confirmed cases have been tied to six outbreaks of measles, including a large one in West Texas. Of states reporting measles infections, Texas has seen the majority of cases so far this year. And recently, Katherine Wells, the director of public health for Lubbock, Texas, expressed concern that the state's current outbreak may be far from over.

Related: Are you protected against measles? Do you need a booster shot? Everything you need to know about immunity

"We are still on the side where we are increasing the number of cases, both because we're still seeing spread and also because we have increased testing capacity, so more people are getting tested," Wells said in a press briefing on March 18, according to STAT News. "I'm really thinking this is going to be a year long in order to get through this entire outbreak."

While Wells specified a potential timeline for the outbreak, other experts are reluctant to estimate exactly when it will end.

"Unfortunately, it is not possible to predict how long the current outbreak of measles in Texas and the adjoining states will last," Dr. Charles Prober, a professor of pediatrics, microbiology and immunology at Stanford University, told Live Science in an email.

So far, case rates are showing no signs of slowing down. Why is that, and how hard is it to control a measles outbreak of this scale?

Reining in control

Numerous factors are needed to control a measles outbreak. These include ensuring that as many people as possible are vaccinated against the disease to build up the population's immunity; and making sure that new cases are detected, isolated and treated promptly, to prevent the disease from spreading.

New cases include those imported when infected individuals enter the country from parts of the world where the disease is prevalent; this can happen when someone from the U.S. vacations in a measles-endemic country and then returns home, for instance.

"As with other communicable diseases, the goal is to detect and isolate cases quickly to prevent further transmission to susceptible individuals," said Gabriel Benavidez, an assistant professor of epidemiology at Baylor University in Texas. "This process requires significant personnel and public health resources, both of which are limited in rural counties in West Texas, making them especially vulnerable," he told Live Science in an email.

He added that "Gaines County, where the vast majority of current cases have occurred, does not have its own public health department, [while] the South Plains Public Health District, which oversees four counties in the region, was quickly overwhelmed by the scale of this outbreak." As of April 8, Gaines County has reported 328 cases of measles, while Terry and Lubbock — the next hardest-hit counties — are each reporting dozens of cases.

Short-term outbreak control measures

Rapidly isolating infected people is particularly important because measles is highly contagious. Measles is caused by a virus called Measles morbillivirus that spreads from one person to next via droplets in the air, which are released when an infected individual coughs or sneezes, for example.

On average, each person infected with measles can pass the disease on to between 12 and 18 others who are susceptible to the disease. By comparison, a person infected with seasonal flu would spread their illness to only one to two susceptible people. The ease with which measles spreads makes outbreaks harder to contain.

And because of how contagious measles is, "the usual prevention methods of isolation, thorough hand-washing, and social distancing may not be as effective at preventing infection," Dr. Robert Amler, the dean of the School of Health Sciences and Practice at New York Medical College, told Live Science.

Furthermore, because measles outbreaks are currently unfolding across multiple states, rather than in a single, isolated population, it could take a lot more resources to get it under control, Wells said at the March 18 press briefing.

Beyond Texas and New Mexico, measles cases have also been confirmed in Alaska, California, Colorado, Florida, Georgia, Kansas, Kentucky, Maryland, Michigan, Minnesota, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, Tennessee, Vermont and Washington. Again, most of the cases reported so far have been linked back to six measles outbreaks, defined as three or more related cases of the disease.

If an infected individual travels to another community with low measles-vaccination rates, they can spark new outbreaks beyond the states that are currently affected, Benavidez said. Preventing these cases from spilling into other communities is key.

Chasing herd immunity

In addition to isolating cases, another way of dealing with an outbreak is to make sure as many people as possible are vaccinated against the disease. If the vaccination rate for measles is more than 95% in a given community, then the number of new cases will be minimal, Prober said. This phenomenon is known as "herd immunity," in which enough of the population is vaccinated and therefore immune to the disease to prevent its circulation, even in those who are not vaccinated.

Herd immunity is important because it helps protect people in the community who are not eligible for the measles vaccine, Amler said. This includes babies who are too young to be vaccinated, as well as people with weakened immune systems, he said.

According to the latest statistics from the CDC, between 2020 and 2021, approximately 91% of children in the U.S. received at least one dose of the measles, mumps and rubella (MMR) vaccine by their second birthday, and 92% of adolescents ages 13 to 17 had received two doses of the vaccine. Two doses are recommended for maximum protection against measles; one dose of the shot is 93% effective against measles infection, while two doses are 97% effective.

However, a torrent of disinformation and misinformation about the measles vaccine may hinder efforts to control the outbreak, experts told Live Science.

This misleading information includes incorrect claims that the outbreak is linked to poor diet and health and that the MMR vaccine can cause autism — a widespread claim that has been categorically disproven by scientists over the years. Robert F. Kennedy, Jr., the current secretary of Health and Human Services, has historically sowed distrust of the measles vaccine and has recently promoted unproven treatments for measles, such as cod liver oil and vitamin A.

"Disinformation and misinformation play a major role [in reducing the ability to control the outbreak] because what is necessary to extinguish this outbreak is for people to use proven, evidence based counter measures," said Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security.

"For measles, that countermeasure is the vaccine," Adalja told Live Science in an email. Ultimately, the best way to avoid measles infections, as well as the fatality or long-term health consequences they can cause, is to get vaccinated, experts say. Standard treatments for measles can alleviate people's symptoms and stabilize their vital signs, but they don't directly treat the disease.

Related: Kids infected with measles face long-term health consequences. Vaccines can prevent all of them.

There is no requirement for states to report to the federal government how many people have been vaccinated against measles, a spokesperson for the Texas Department of State Health Services (DSHS) told ABC News. Therefore, it can be difficult to tell what percentage of the population has been vaccinated and thus whether that key 95% threshold has been hit.

Vaccination rates do appear to now be on the rise, though. As of March 11, nearly 9,000 people in New Mexico — the second most badly affected state behind Texas — received the MMR vaccine since the start of the year. That's compared to 5,342 in the same time period last year, according to state figures. Meanwhile, in Texas, at least 173,362 people received a dose of the MMR vaccine between Jan. 1 and March 16 this year, an increase compared with the number of doses administered between the same dates last year, ABC News reported.

After a vaccination, it takes around two weeks for an individual to build up immunity to the measles virus. So a person would be considered fully vaccinated two weeks after their second dose.

The path forward

If the Texas outbreak continues for more than a year, it's possible that measles will no longer be considered "eliminated" in the U.S. According to the CDC, elimination means that a disease has not constantly circulated within the population for at least 12 months and that the population has a "well-performing" surveillance system to keep the disease in check. For a disease to be "eradicated," its transmission would have to be driven to zero worldwide, as is the case with smallpox.

Measles was declared eliminated in the U.S. in 2000, thanks to extensive vaccination efforts and enhanced measles control across the Americas at large. However, as the disease is still prevalent elsewhere in the world, outbreaks do still occur in the U.S. as the disease is occasionally imported from other countries. In 2024, for example, there were 285 confirmed cases of measles in the U.S., and in 2023, there were 59 cases.

There is still hope to rein in the current outbreak, provided that people get vaccinated. Otherwise, the virus will continue to infect susceptible individuals, Amler said. "If we can find them [vulnerable individuals] first and vaccinate them, the outbreak will stop."

It is also essential that local public health departments and their leaders are able to serve as trusted sources of medical information in their communities, Benavidez said.

"This is a challenge not only in Texas but across the country," he said. "Preventing future outbreaks will require rebuilding trust in public health, particularly among populations that are hesitant or skeptical about vaccines and other public health measures."

Building trust in the face of rampant misinformation isn't easy, he added. "That trust must be built through cultural sensitivity, understanding, and a genuine effort to engage with the reasons behind vaccine hesitancy — without this foundation, the risk of recurring outbreaks will remain."

This article is for informational purposes only and is not meant to offer medical advice.

Vaccines for infectious diseases have changed the trajectory of humankind. In the 20th century alone, smallpox killed more than 300 million people worldwide, and polio killed or paralyzed half a million people each year. Today, thanks to vaccines, smallpox has been eradicated worldwide, meaning it's essentially extinct; and polio has been eliminated in many countries, so the disease is no longer endemic to those places.

With the success of vaccines for infectious diseases in mind, scientists have wondered if it might be possible to similarly harness the power of the immune system against other conditions. Now, researchers are working to develop vaccines for cancer.

But what, exactly, are cancer vaccines, and how do they work?

Related: The 10 deadliest cancers, and why there's no cure

How do regular vaccines work?

Vaccines, broadly, are substances that train the immune system to defend the body against a dangerous invader. They help the immune system recognize a pathogen by exposing the body to key features of that germ, such as proteins from a virus's surface. These features are called antigens, and when they're introduced through a vaccine, the immune system learns to recognize them as a threat.

Once the immune system becomes familiar with antigens from a virus or bacterium, it will then be able to quickly mount an attack against that pathogen if it ever comes into contact with the bona fide germ. That's how vaccines stop people from contracting infectious diseases, such as smallpox or measles. If a vaccine doesn't completely block an infection from happening, it can still make the resulting illness much less dangerous — think of the annual flu shot.

"They [vaccines] harness the inbuilt ability of our immune systems to recognize something that is foreign to our bodies," Dr. Vinod Balachandran, director of the Olayan Center for Cancer Vaccines at Memorial Sloan Kettering Cancer Center, told Live Science.

Some common vaccines against infectious diseases already help prevent cancer. The human papillomavirus (HPV) vaccine, for example, protects against the strains of HPV that are most likely to cause cervical cancer, and the hepatitis B vaccine protects against liver cancer caused by chronic hepatitis B infections. But these vaccines don't actually target the cancer itself; they instead take aim at viruses that increase the risk of cancer.

How do cancer vaccines work?

In contrast, when scientists talk about a "cancer vaccine," they're referring to a vaccine that targets cancer directly, rather than using the indirect methods mentioned above, Balachandran said.

Harnessing the immune system to fight cancer with a vaccine is tricky, though, because vaccines rely on the immune system's recognition of a pathogen as a foreign invader. But cancer grows from our own cells — and that means the genetic and molecular compositions of a cancer cell are relatively similar to those of a healthy one.

However, certain molecules are found only in cancer cells, and researchers are attempting to use those molecules to train the immune system to fight cancer. They call these molecules neoantigens, and they're introduced to healthy cells through processes such as genetic mutation.

"If you can identify the neoantigens in a cancer that the immune system can recognize, you can teach the immune system to recognize a cancer as foreign," Balachandran explained.

There are some neoantigens that everyone with a certain type of cancer may have, but neoantigens can also be specific to an individual. Researchers are still investigating the most effective neoantigens to target for different types of cancer. Unlike vaccines for infectious diseases, Balachandran said, cancer vaccines will likely need to be designed for individual patients, or made in small batches, to ensure they're targeting these different neoantigens efficiently.

In his own lab, Balachandran is conducting small trials with human patients to develop a vaccine for a deadly form of pancreatic cancer. After surgically removing patients' tumors, Balachandran gave the participants a regimen of immune-boosting and chemotherapy drugs alongside a personalized vaccine that targets specific neoantigens seen in their tumors. The vaccines contain mRNA, a genetic molecule that, in this case, carries blueprints for the neoantigens. Once inside the patient, the vaccine enables cells to build those neoantigens and show them to the immune system.

Related: New mRNA vaccine for deadly brain cancer triggers a strong immune response

Half of the vaccinated patients in the 16-person trial showed a boost in cancer-fighting immune molecules, and their cancers didn't return for the duration of the 18-month study. These results suggest that, at least in some patients, personalized cancer vaccines could decrease the likelihood that deadly cancers will return.

Do cancer vaccines treat cancer, or do they prevent it?

Balachandran explained that currently, many cancer vaccines are targeted at what physicians call "secondary prevention." This means that they're designed to stop cancer from returning in a person that's currently in remission, rather than preventing cancer from emerging in the first place.

That said, there are also therapeutic cancer vaccines that can treat existing cancers. These work like immunotherapies for cancer, by revving up the immune system to fight tumors.

As of 2025, one therapeutic cancer vaccine has been approved by the U.S. Food and Drug Administration. This vaccine, called sipuleucel-T (brand name Provenge), helps direct the immune system to attack a typically incurable form of prostate cancer. The vaccine contains a patient's own cells, which have been "activated" in the lab through exposure to a prostate-cancer protein. Trials suggest the treatment extends patients' survival by a few months.

Scientists are investigating many more cancer vaccines, including some for brain cancer and skin cancer, in clinical trials. Different vaccines are at different points in the clinical trial process; some are still in early research, whereas others, such as Merck and Moderna's vaccine for melanoma, are in the final stage of clinical trials..

If current efforts to design cancer vaccines for secondary prevention are successful, Balachandran hopes that researchers could one day design cancer vaccines for primary prevention — stopping people from ever developing cancer in the first place. A vaccine for primary prevention would work more like a traditional shot for infectious diseases by blocking the condition from ever emerging.

"If we now know that the immune system can also recognize cancer, it should, in theory, be possible to develop a vaccine against cancer, like we have been able to do against pathogens," Balachandran said. "It's an exciting time for the field right now."

This article is for informational purposes only and is not meant to offer medical advice.

The Centers for Disease Control and Prevention (CDC) has narrowed its recommendations for which older adults should get a vaccine against respiratory syncytial virus (RSV). It now states that only adults 75 and older, or those ages 60 to 74 who are at high risk, should get the shot.

That's partly because the vaccine may slightly increase the risk of a rare side effect that can sometimes lead to paralysis or death.

RSV circulates seasonally and hospitalizes 60,000 to 160,000 older adults in the U.S. each year. An estimated 6,000 to 10,000 people in this age group die due to RSV infection annually. The first-ever RSV vaccine was approved last year, and a total of three have now been approved for use in people ages 60 and up: GSK's Arexvy, Pfizer's Abrysvo and, most recently, Moderna's mResvia.

Initially, the CDC said all adults ages 60 and older could get one dose of one of these RSV vaccines after discussing it with their doctor.

Related: FDA approves 1st RSV vaccine for use in pregnancy to stop infection in newborns

Now, "based on currently available evidence," the CDC's Advisory Committee on Immunization Practices has concluded that the benefits of RSV vaccination do not clearly outweigh the potential harms in adults ages 60 to 74 who don't have risk factors for severe RSV. However, people in this age range who do have risk factors could still benefit.

With that in mind, "providers should continue to have flexibility in offering RSV vaccine to patients they assess to be at increased risk for severe disease even if they do not fall into an explicitly named risk category," the CDC noted in a Morbidity and Mortality Weekly Report published Tuesday (Aug. 6).

Thus, people ages 60 to 74 can still consider the shot if they are at high risk of severe RSV infections. That would apply to people with chronic heart disease or a weakened immune system, as well as those who live in long-term care facilities such as nursing homes.

Adults who have already received an RSV vaccine "should not receive another dose," the report notes.

The updated recommendations were issued because of higher-than-expected rates of Guillain-Barré syndrome (GBS) tied to the vaccines. GBS can cause tingling, numbness and muscle weakness and sometimes progress to paralysis. In severe cases, the condition can affect muscles that support breathing and thus be life-threatening.

The GSK and Pfizer RSV vaccine trials in older adults hinted at this elevated risk. However, the trials were too small to confirm that the shots themselves increased rates of GBS. Now that the shots have been in wider use for about a year, a clearer picture has emerged: The rate among vaccine recipients is higher than the expected background rate of GBS in this age group.

For a vaccine with no associated risk of GBS, you'd expect to see about 2 cases per 1 million doses administered, whereas the Pfizer vaccine was tied to about 5 cases per 1 million, Live Science previously reported.

Thus, data suggest that the overall risk of developing the condition is still quite low, but this slight bump in risk was still a factor experts weighed when reevaluating their vaccine recommendations.

(Notably, there wasn't an uptick in GBS in the trials of Moderna's RSV vaccine — but that shot has only recently been approved, so wider surveillance hasn't yet been conducted.)

The new CDC guidelines don't tell people to discuss the risks and benefits of the shots with their doctors. Now, the recommendations are explicitly based on age and on known risk factors. Especially for people ages 75 and older, the benefits are clear, the CDC argues.

The previous recommendations were less direct, and doctors found them "confusing and time-consuming" to implement, the report notes. As a result, RSV vaccine coverage was similar for adults with risk factors and for those without, whereas ideally, at-risk populations would see higher rates.

As of spring 2024, an estimated 20% to 25% of U.S. adults ages 60 and older had received an RSV vaccine.

This article is for informational purposes only and is not meant to offer medical advice.

Ever wonder why some people build muscle more easily than others or why freckles come out in the sun? Send us your questions about how the human body works to community@livescience.com with the subject line "Health Desk Q," and you may see your question answered on the website!

New research on "forever chemicals" called PFAS has added to growing concerns about their potential effects on human health.

PFAS, or perfluoroalkyl and polyfluoroalkyl substances, are chemicals used in many household products. We've known for years that they can enter our bodies through the food and water we consume. But recently, scientists showed for the first time that some PFAS can be absorbed through the skin and into the bloodstream.

Previously, skin was thought to act as a barrier against PFAS, which have been tied to a range of concerning health effects. Many everyday items our skin touches, including makeup and fabrics, can contain these chemicals.

So, what do we know about the effects of PFAS on our health?

Related: PFAS 'forever chemicals' to officially be removed from food packaging, FDA says

How do PFAS get in the body?

PFAS are human-made chemicals that have been used since the 1940s and are still found in many products, including nonstick cookware, waterproof clothing, cosmetics and dental floss. They are largely prized for being nonstick; repellent to water, oils and stains; and flame retardant. They are sometimes added to products to improve their texture or shine.

Current estimates suggest that nearly 15,000 different PFAS have been invented, and more continue to be developed.

PFAS take thousands of years to break down and thus accumulate in the environment and in humans' and animals' bodies. They are found in soil, food, air and drinking water, as well as in the blood of most people in the U.S. 

One way they enter human blood may be through the skin, recent research suggests. Published in May in the journal Environmental International, the study measured the absorption of 17 commonly used PFAS using 3D models made from lab-grown human skin. 

"We found that most of the PFAS we included in our study can absorb into human skin," Oddný Ragnarsdóttir, who led the study as part of her doctorate at the University of Birmingham in the U.K., told Live Science. At this point, though, it's unclear what doses of PFAS people would realistically be exposed to via skin contact, and how harmful those doses are.

PFAS have also been found in breast milk, and more than 40 studies have found them in cord blood collected at birth. Recent research, published in May in the journal Eco-Environment & Health, showed that PFAS readily travel across the placenta. This backs evidence that many people may first be exposed to PFAS before birth.

Related: Scientists find a simple way to destroy 'forever chemicals'

What do PFAS do to the body?

Once in the bloodstream, PFAS bind to proteins and can enter cells and organs, where they remain for years or even decades. Scientists are still learning about the health effects of different PFAS, but there's some evidence of their potential harms.

In 2016, the National Toxicology Program published a review about the two most common PFAS: perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). The review primarily considered experiments in lab animals and epidemiological studies in people, which looked for links between PFAS exposure and health effects at a population level. 

It concluded that both PFOA and PFOS are likely "immune hazards to humans." The strongest evidence suggests both PFOA and PFOS can hinder antibody responses. Weaker evidence linked PFOA to a higher risk of autoimmune disease and allergies in humans, while in animals, PFOS suppress natural killer cells, which normally destroy diseased cells, including cancer. 

What is less clear, the review noted, is exactly how PFOA and PFOS produce these effects. 

More recent studies have started to unravel this, finding that PFAS can alter the function of various proteins that are either made by the body or obtained through diet. In addition, a 2023 review by the World Health Organization's International Agency for Research on Cancer (IARC) found "strong mechanistic evidence" linking PFOA and PFOS to epigenetic changes, meaning molecular changes that affect how genes are activated. For PFOA, there was also "sufficient" evidence of the chemical being able to cause cancer in lab animals, while similar evidence was "limited" for PFOS. 

As a result, in 2023, the IARC classified PFOA as "carcinogenic to humans" and PFOS as "possibly carcinogenic to humans." The agency's classifications aren't related to how much a substance might increase cancer risk but rather how conclusively the IARC can say it causes cancer at all. In that respect, the evidence is stronger for PFOA than for PFOS.

Related: More than 50 new environmental chemicals detected in people

Studies also suggest that PFAS might affect reproductive health. A 2021 review found that exposure to PFOA and PFOS were both associated with lower testosterone levels and semen quality in men, at a population level.

Exposure to PFAS in the womb has also been linked to lower antibody responses to childhood vaccines, such as those for diphtheria, rubella and mumps. This early exposure is also linked to changes in how teens and young adults break down fats and proteins; there's concern that this might raise the risk of metabolic diseases. 

Beyond PFOA and PFOS, thousands of other PFAS are yet to be studied. One big thing we don't know yet is which PFAS are in which products and at what concentrations, said Stuart Harrad, a professor of environmental chemistry at the University of Birmingham and senior author of the recent study on PFAS skin absorption. 

"If a PFAS that is well absorbed is present in high concentrations in a cosmetic or fabric with which we have prolonged skin contact," Harrad said, "then the resultant exposure will be substantial and may be on a par with what we receive via our diet or drinking water."  

With precise measurements of the doses people are exposed to through the skin, toxicologists and epidemiologists could begin to evaluate the health effects of those doses, he said.

What now?

PFOS and PFOA have steadily been phased out of U.S. production since the early 2000s. This has resulted in their decline in blood levels over the past two decades, but the chemicals persist in the environment and are still used in other countries. In addition, new, less-studied PFAS have arisen to replace those two. 

"As 'old' PFAS are phased out or banned, 'new' ones have been introduced," said Andrew Watterson, a public health researcher at the University of Stirling in Scotland. 

"The cumulative and total risks to workers making, applying and exposed to many PFAS, and to consumers and the public who come into contact with PFAS and the wider environment, have still not been fully assessed," he told Live Science in an email. "The data gaps that still exist for chemicals that have been used for decades are very worrying."

Federal agencies and states are making efforts to limit PFAS in water and consumer products. However, removing PFAS from our bodies and the environment will be difficult and costly. 

In the meantime, the Environmental Protection Agency has released an updated guide on how consumers can reduce their PFAS exposure. It advises people to install in-house water filters; to avoid eating fish from contaminated waterways; and to avoid PFAS-treated fabrics and other household products known to contain PFAS.

Consumers may be able to pressure manufacturers to remove or reduce PFAS in their products, Watterson said. But in general, there is little the public can do to avoid contact with chemicals already present in the environment, he said. Solutions will require regulating all PFAS, he said, and ultimately cutting them off at their sources.

This article is for informational purposes only and is not meant to offer medical advice.

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The new RSV vaccines approved for older adults may be linked to a slightly increased risk of a rare neurological condition, a recent analysis finds. 

However, the Centers for Disease Control and Prevention (CDC) says the benefits of the vaccines outweigh this slight increased risk. Therefore, the agency still recommends that adults 60 years and older get an RSV vaccine in consultation with their doctor. The available vaccines include one called Arexvy and another called Abrysvo.

The recent research — published May 30 by CDC scientists in the agency's Morbidity and Mortality Weekly Report — is consistent with findings in the clinical trials for the vaccines, according to study leader Anne Hause, an epidemiologist and program lead for V-safe in the CDC's Immunization Safety Office. During clinical trials, researchers observed higher-than-expected rates of Guillain-Barré syndrome, a disorder in which the immune system attacks healthy nerves. 

While Guillain-Barré syndrome was noted as a potential concern during the trials, the trials were too small to tease out any possible connection to the shots. Real-world monitoring data involves much larger groups of patients and thus helps confirm the link that trial data hinted at.

Related: Who should get the new RSV vaccines? Here's everything you need to know

Guillain-Barré syndrome causes tingling, numbness and muscle weakness, and it can progress to paralysis. According to the Mayo Clinic, most people recover completely from this illness, but it can take months or years. In severe cases, the condition can affect the muscles that support breathing and be life-threatening.

While Guillain-Barré is fairly rare, RSV, or respiratory syncytial virus, circulates every year and poses a threat to children and older adults, in particular. Among U.S. adults over 65, the seasonal infection kills approximately 6,000 to 10,000 people each year, according to the CDC.

The two new vaccines, one produced by Pfizer and the other by GSK, were approved for older adults in May 2023. The new CDC report examines the first year of safety data using surveys of patients, as well as the Vaccine Adverse Event Reporting System (VAERS), a database where anyone can submit suspected vaccine reactions.

The analysis showed that there were five reports of Guillain-Barré syndrome for every million doses of Pfizer RSV vaccine administered, amounting to 17 cases in total. There were 1.5 reports per million doses of GSK RSV vaccine, or 11 cases in total.

These rates were higher than the background rate of Guillain-Barré expected in this population. This background rate was based on the rates in people given mRNA-based COVID vaccines, which were not tied to any uptick in the syndrome.

However, because VAERS is based on voluntary self-reporting, researchers can't confidently tie every case to the RSV vaccinations, Hause emphasized. Because of this uncertainty, "CDC and FDA are conducting additional safety evaluations in other vaccine safety systems," she said. 

Guillain-Barré syndrome often appears after an infection with viruses or bacteria, said Maria Pino, a pharmacologist and associate professor at the New York Institute of Technology's medical school who has written about the RSV vaccines. Similar to the new shots, a 1976 swine flu vaccine was also linked with a slightly increased risk of the syndrome. 

The precise link between some infections and vaccinations and the autoimmune syndrome is unknown. However, it likely has something to do with the body's natural immune response to these types of triggers going rogue and turning against the wrong target, Pino told Live Science. 

Health officials still recommend getting the RSV vaccines because the risk of developing Guillain-Barré is so low compared with the risk posed by an RSV infection, said Dr. Simon Drysdale, a pediatric infectious disease specialist in the Oxford Vaccine Group. For adults over 60 living in high-income countries, their risk of dying from RSV if they're hospitalized with the infection is 7%, Drysdale said, citing 2023 research published in the journal Influenza and Other Respiratory Viruses. 

Unlike the flu or COVID-19, there is no antiviral treatment available for RSV. Rather, treatment involves maintaining a person's vitals in the hope the infection subsides on its own. 

"You've got a very, very, very small risk of a significant side effect [from vaccination], versus a much higher risk of having a significant outcome from having RSV disease," Drysdale told Live Science.

For patients deciding whether to get an RSV vaccine, the best source of information is always their own doctor, Pino said. During that discussion, doctors and patients can weigh that specific person's risk factors for RSV complications. Those who face a heightened risk include people with compromised immune function, chronic lung disease and chronic heart disease, as well as those ages 75 and older and those living in long-term care facilities, Hause said.

Other risk factors include frequent contact with children, who carry and spread the virus easily, Drysdale said, as well as chronic kidney disease, which is associated with a high risk of hospitalization from RSV. 

"For the vast majority of people," Drysdale said, "the benefit is going to significantly outweigh the risk." 

This article is for informational purposes only and is not meant to offer medical advice.

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More than 570 cases of mpox have been detected in the U.S. so far in 2024 — nearly double the number seen by this time last year.

This infection rate doesn't come close to that seen at the peak of the mpox outbreak in early August 2022, when the U.S. saw an average of about 470 new cases in a week. However, the new data highlight that mpox is still circulating and that there's still a need for people who are at risk of infection to get vaccinated.

The most widely used mpox vaccine in the U.S., called JYNNEOS, is given in two doses spaced a month apart. A person is fully vaccinated two weeks after their second dose, and no booster shots are currently recommended. You can check whether you're eligible for the vaccine and where to get the shots on the Centers for Disease Control and Prevention (CDC) website. Various local health departments, such as those of New York City and San Francisco, also have their own vaccine-site finders.

The vaccine is not widely recommended to everyone. Rather, select groups — for example, gay and bisexual men with recent sexually transmitted infection (STI) diagnoses — have been identified as at risk of mpox and made eligible for the shots.

Related: Should everyone get a monkeypox vaccine?

"Most of the cases that we're seeing reported are either unvaccinated or under-vaccinated, meaning they either never received a vaccine, or they only got one dose," Dr. Jenni McQuiston, deputy director of the CDC's High-Consequence Pathogens and Pathology division, told ABC News.

Mpox, formerly known as monkeypox, is caused by a relative of the now-eradicated variola virus, which causes smallpox. Mpox viruses come in two broad types: clade I and clade II. Clade I is more likely than clade II to cause severe and fatal disease. Although clade I has not been detected in the U.S. to date, it's possible that travelers could carry the viruses to the country from other places, such as the Democratic Republic of the Congo, the CDC cautioned in December 2023. The JYNNEOS vaccine guards against both clades.

In general, mpox viruses can cause flu-like symptoms, such as fever, muscle aches, fatigue and swollen lymph nodes. However, during the outbreak's peak in 2022, not all cases involved such symptoms. The disease's characteristic pox rashes typically start out as discolored patches and then progress to raised bumps, blisters, and large, pus-filled pimples that scab over and slough off. Depending on the case, these rashes may first appear around the face and in the oral cavity and then spread to the extremities, or they may initially show up around the genitals and anus.

People with severely weakened immune systems, including those with HIV; children younger than 1 year; people with a history of eczema; and people who are pregnant face a higher risk of severe disease from mpox. The disease most often spreads through close contact with an infected person, especially through contact with their rashes.

Since May 2022, when the mpox outbreak hit the U.S., the country has seen more than 30,000 cases, most of which occurred in 2022. By the start of 2023, infection rates had slowed — the U.S. recorded 298 cases between Jan. 1 and March 23, 2023. Compare that to this year, when 576 cases were reported in the same time frame, according to the CDC. (The agency adds that these case counts are provisional and subject to change.)

More than 110 of the cases this year were in New York City, 64 were in California and 50 were in Florida.

Anyone can catch mpox, but from the start of the outbreak, the disease has disproportionately affected gender-diverse and transgender people and also men who have sex with men. People in these groups who have had recent STI diagnoses or who have had more than one recent sex partner are recommended to get vaccinated for mpox.

However, CDC data suggest that mpox vaccination among these and other at-risk groups is not as high as it should be, with large portions of the at-risk population missing one or both vaccine doses.

"We felt like it was really important to get the word out that there is a continued risk from this virus. It's still here," Dr. Brandy Darby, director of the Division of Surveillance and Investigation in the Office of Epidemiology at the Virginia Department of Health, told CNN. The department recently issued a notice about the dozen mpox cases it's seen so far in 2024, in part because it saw 12 in all of 2023.

"We also wanted to give people time to protect themselves ahead of Pride season" in June, Darby said. "We're hoping this might encourage people to go ahead and get vaccinated so they can go out and enjoy their celebrations and not have to worry so much about mpox."

This article is for informational purposes only and is not meant to offer medical advice.

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The number of measles cases reported in the U.S. so far this year has already surpassed the total number of infections counted in 2023.

According to data released by the Centers for Disease Control and Prevention (CDC), 64 confirmed and suspected cases of measles had been reported across 17 states as of March 21. Last year, 58 total cases were reported in 19 states and Washington D.C.

This year's case count hasn't yet smashed records seen in the past decade. 2014 and 2019 stand out as particularly bad years, with more than 660 and 1,200 measles cases apiece; these high numbers partly stemmed from major outbreaks tied to Disneyland and to underimmunized, close-knit religious communities.

However, measles cases have rebounded significantly since 2020, when only 13 infections were reported in the U.S. And internationally, Austria, the Philippines, Romania and the U.K. are experiencing outbreaks, the CDC cautioned in a recent health advisory.

Related: Measles deaths jumped over 40% from 2021 to 2022, CDC reports

"Given currently high population immunity against measles in most U.S. communities, the risk of widescale spread is low," the advisory reads. "However, pockets of low coverage leave some communities at higher risk for outbreaks."

At the time of the advisory, issued March 18, 58 of this year's measles cases had been confirmed by the CDC. The vast majority, over 90%, were tied to international travel, the CDC reported, while some have been tied to domestic travel to Florida, according to CBS. Most cases were reported in unvaccinated children ages 1 year and older.

The CDC recommends that children receive their first measles-mumps-rubella (MMR) dose at 12 to 15 months old and a second shot between 4 and 6 years old. But kids at least 6 months old who will be traveling internationally should receive at least one dose of MMR vaccine before departing, according to the CDC.

Recently, the percentage of U.S. kindergarteners who have not completed their measles vaccination has grown, leaving an estimated 250,000 kindergartners susceptible to the infection each year for the last three years, the CDC reported. The goal is to have at least 95% of kindergarteners in a given community vaccinated, to minimize opportunities for the virus to find a vulnerable host and spread — but during the 2022-2023 school year, most states didn't hit that 95% target, in part due to an uptick in vaccine exemptions.

Similar dips in routine measles vaccinations are being seen around the globe.

"This is why it's urgent for us to sort of address vaccination so that we can really decelerate sort of the march of measles, given the global scenario as well as what we're seeing with some vaccination rates in the country," Dr. Demetre Daskalakis, director of the CDC's National Center for Immunization and Respiratory Diseases, told CBS.

This article is for informational purposes only and is not meant to offer medical advice.

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A Pfizer-made vaccine that protects older adults from respiratory syncytial virus (RSV) is highly effective for two consecutive seasons, new data show.

RSV is a common respiratory virus that typically spreads between fall and spring, and it hits adults over age 65 particularly hard. In this age group in the U.S., the virus causes 60,000 to 160,000 hospitalizations each year and about 6,000 to 10,000 deaths, according to the Centers for Disease Control and Prevention (CDC).

Last year, two RSV vaccines were approved for use in adults ages 60 and older: GSK's Arexvy and Pfizer's Abrysvo; the latter is also approved for pregnant people, whose newborns would be at risk of severe RSV without some form of protection. Now, new clinical-trial data released by Pfizer show that one dose of its vaccine "maintained consistently high protective efficacy" in older adults across two consecutive RSV seasons.

Related: Who should get the new RSV vaccines? Here's everything you need to know

The trial looked at how well the shot guards against "lower respiratory tract disease," or infections involving the lungs, Pfizer reported Thursday (Feb. 29). On that front, the vaccine was 88.9% effective in the first RSV season after administration and 77.8% effective in the second. The shot worked equally well against the two major subtypes of the virus: RSV A and RSV B.

The vaccine also showed decent protection against less-severe RSV infections, defined in the trial as triggering fewer symptoms than the more-severe cases, Pfizer reported. In this respect, the vaccine was 65.1% effective in the first season and 55.7% effective in the second.

These data will likely influence whether the CDC will recommend that older adults get RSV shots annually or every other year, CNBC reported.

The CDC hasn't recommended that all older adults get an RSV vaccine, whether Pfizer or GSK. Instead, the agency recommends that individuals discuss the risks and benefits of the shots with a doctor. That's partly because there were a handful of "inflammatory neurologic events" reported in trials of both vaccines. These events were rare among the thousands of people in the trials, but they included Guillain-Barré syndrome (GBS), a condition in which the immune system attacks the nerves in a way that can be life-threatening in severe cases.

New data presented Thursday by a CDC advisory committee show slightly higher rates of GBS with the Pfizer shot than with the GSK vaccine, STAT reported. However, cases of GBS were seen in recipients of both shots, and experts say it's too soon to know if the vaccines directly triggered those cases.

"Some of these data and findings are based on small numbers of cases and relatively small numbers of doses administered," Dr. Tom Shimabukuro, former director of the CDC's immunization safety office, told STAT. "And due to uncertainties and limitations, based on these early data we can't establish if there is an increased risk for GBS after RSV vaccination in these individuals 60 and older."

GBS can cause muscle weakness, paralysis and changes in sensation, and it most commonly affects adults over 50; severe cases that affect a person's ability to breathe can be life-threatening, but mild cases sometimes cause only brief weakness. 

Most cases manifest in the wake of a bacterial or viral infection. And some vaccines, such as the flu shot, have been tied to a very slightly increased risk of GBS. (For the flu shot, there might be one or two extra cases of GBS out of a million vaccinated people, compared with expected background rates of the condition in the population, according to STAT.)

As of mid-February, CDC analysts have flagged 23 cases of GBS among 9.5 million people who have been vaccinated with either the Pfizer or GSK vaccine, with 15 cases tied to Pfizer. However, the data are somewhat muddy, because 14 of the 23 people had also received a second shot — such as a flu or shingles vaccine — at the same time as their RSV shot.

Overall, both shots are still considered very safe, as their most common side effects are mild. Currently, the CDC is mulling over the new safety and effectiveness data in the interest of updating the recommendations for both vaccines. The updated recommendations are expected in the summer, CNBC reported.

This article is for informational purposes only and is not meant to offer medical advice.

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Rare blood clots tied to some early COVID-19 vaccines that are no longer in use may have been the result of two out-of-control immune reactions happening at once.

One of these immune reactions was already known, but the second, reported Oct. 26 in the journal Blood, is a new discovery.

The finding could help to explain how other clotting conditions develop and point to better treatments, as well as suggest ways to make vaccines safer for people who are prone to the side effect.

"Understanding how a drug causes an adverse event allows us to design new approaches to make those treatments safer," said Ishac Nazy, an associate professor of medicine at McMaster University in Canada who studies the vaccine-related clotting disorder but was not involved in the current research.

A rare side effect

The vaccine-related clotting disorder, known as vaccine-induced immune thrombotic thrombocytopenia (VITT), was rare and linked to two shots: the Johnson & Johnson (J&J) and AstraZeneca COVID-19 vaccines. Both shots contained common-cold viruses called adenoviruses that were tweaked so that they couldn't infect cells. Instead, the modified viruses carried DNA instructions for part of SARS-CoV-2, the coronavirus that causes COVID-19, into the body.

VITT was a sobering side effect of what many public health experts had hoped would be a promising technology. Unlike the Moderna and Pfizer-BioNTech COVID-19 shots, which contain RNA, the J&J and AstraZeneca vaccines did not need ultracold storage, making them more accessible where cold-chain storage is unreliable. Adenovirus-based vaccines have been investigated for other diseases, but very few have achieved approval. Exceptions are an adenovirus-based Ebola vaccine approved in China and another approved by the European Union, both used only in at-risk individuals.

Soon after rolling out the J&J and AstraZeneca vaccines, doctors began reporting cases of clotting that looked a lot like a previously known disorder called Heparin-induced thrombocytopenia (HIT). About 20 to 30 years ago, HIT affected 3.5% of patients who had knee or hip replacements, said Dr. Andreas Greinacher, a physician who specializes in clotting disorders at the Greifswald University Hospital in Germany and was not involved in the new research. In these patients, heparin, a blood thinner normally given to prevent blood clots, actually triggered runaway clotting instead.

The adenovirus-based COVID vaccines were triggering the same condition as HIT, though scientists gave it a new acronym to reflect the different origin. Researchers reported that about 1 in 50,000 people under 50 who received the vaccine were affected, as well as about 1 in 100,000 of those 50 and older.

Neither vaccine is currently administered in the U.S. (AstraZeneca's shot was never used in the country, and J&J's vaccine was authorized but then retired due to the clotting issue and availability of better vaccines.) However, learning what triggers VITT could still be useful.

Today, HIT is rare because doctors now understand what causes it and can prescribe different, safer versions of heparin, Greinacher told Live Science. Similarly, he said, studying the mechanisms behind HIT and VITT could make adenovirus vaccines safer.

"Our big aim currently is to find which factor in the vaccines is triggering it," Greinacher said. "If you know the factor, I'm certain there are very smart biotechnologists who can modify the adenovirus vector so this factor is no longer present."

Unraveling VITT

When VITT was first observed in patients getting COVID-19 vaccines in February 2021, scientists soon discovered that it had to do with PF4, a chemical signal released by platelets, the blood cells that form clots.

In rare cases after vaccination with an adenovirus-based vaccine, the body would make antibodies to PF4. These antibodies would latch onto PF4 and form clumps that could then bind to receptors called Fc on other platelets. This would activate the platelets and lead to a runaway clotting response.

The new Blood study found that PF4 alone also activates a second set of receptors that cause platelets to accumulate, likely a second reason why clotting goes haywire in this disorder.

There is still a long way to go, Nazy told Live Science, whose team first reported in 2021 how antibodies against PF4 were causing VITT. The new research suggests that there are actually two different ways that PF4 acts in VITT, he said. These two pathways are not exclusive and may work in tandem.

In the new study, researchers tested blood from healthy individuals and people with VITT to trace the cascade of signals that leads to the overactive clotting. They found that the PF4 activates a receptor called c-Mpl on platelets, which causes them to clump together. This is in addition to the mechanism discovered in 2021, in which complexes of PF4 and PF4 antibodies activate platelets' Fc receptors.

"What we have shown is that as well as that antibody trigger, you've also got PF4 itself binding to platelets and activating them, providing a double whammy," Phillip Nicolson, an associate clinical professor of cardiovascular medicine at the University of Birmingham in the U.K. and the leader of the new study, told Live Science. "That may be why [the clotting] happens to a harmful degree."

Scientists have a few clues as to why adenovirus vaccines can trigger this response. PF4 carries a positive electrical charge on its surface, while adenoviruses are highly negatively charged, Nicolson said, so they may bind together easily. But even that is not confirmed, Nazy said, and has mostly been shown with computer modeling rather than with real molecules.

In rare cases, unusual clotting happens without vaccination or treatment with heparin. A recent paper published in the The New England Journal of Medicine, and co-authored by Nazy, found that in at least two of these unexplained clotting cases, the clotting disorder occurred after typical adenovirus infections. In many cases, the connection between unexplained clotting and a viral infection may be missed. And it's still a mystery why very few people are susceptible to these clotting conditions.

"That's the part we need to understand to prevent the disease from even happening," Nazy said.

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Hospitalization is supposed to make people well. But on a given day, an estimated 1 in 31 hospitalized patients contracts an infection from the hospital itself, and tens of thousands die annually. Many of these infections are antibiotic-resistant, and treating them contributes to the evolution of new "superbugs."

But now, researchers have a new idea for preventing hospital-acquired infections: a vaccine that puts the immune system on short-term high alert for a broad array of pathogens.

The vaccine, so far tested only in mice, activates the innate immune system, the body's first line of defense, according to a study published Oct. 4 in the journal Science Translational Medicine. The innate immune system is not specific to any particular pathogen, and its protection tends to fade faster than that of the adaptive immune system, which "remembers" viruses and bacteria it has encountered in the past. (Most vaccines train the adaptive immune system to fight off specific diseases, such as the seasonal flu or COVID-19.)

But for hospitalized patients, broad and short-term protection is needed most, said Brad Spellberg, the senior study author and chief medical officer at the Los Angeles General Medical Center.

"It solves a problem that traditional vaccines have not been able to solve," Spellberg told Live Science.

Related: Dangerous 'superbugs' are a growing threat, and antibiotics can't stop their rise. What can?

There are too many potential hospital-acquired pathogens to reasonably vaccinate incoming patients for each individual bacterium or fungus, Spellberg said. And in any case, traditional vaccines require time to activate adaptive immunity, and hospitalized patients need immediate protection.

The researchers stumbled across the idea for the new vaccine more than 15 years ago while looking to develop a traditional vaccine for Staphylococcus aureus, a common source of hospital infections. Certain strains of the bacterium, known as methicillin-resistant S. aureus (MRSA), are resistant to common antibiotic treatments. 

The researchers were struggling to find a combination of bacterial proteins that would protect against staph infections in the blood, so they began adding a series of compounds called adjuvants to their formulation. Adjuvants are ingredients that broadly boost the immune response to a desired target.

Eventually, the researchers found a combination of three bacterial proteins and three adjuvants that worked in animal studies. But during testing, they found that giving mice a vaccine with only the three adjuvants was just as protective as giving them the vaccine with proteins and adjuvants combined.

"We were like, 'Whoa, whoa, whoa, what is going on here?'" Spellberg said.

What was going on, another decade of testing revealed, was that the vaccine was not specifically targeting the staph proteins. Rather, it was boosting the activity of the innate immune system more broadly — and that was enough to protect the mice from staph infection.

"It's an important and exciting concept for a vaccine," said Marcela Henao Tamayo, an immunologist at Colorado State University who was not involved in the new study.

The three adjuvants — aluminum hydroxide, monophosphoryl lipid A, and fungal mannan — protected mice against not only S. aureus but also strains of other common hospital-acquired pathogens with various degrees of antibiotic resistance, such as Enterococcus faecalis, Escherichia coli, Acinetobacter baumannii and Klebsiella pneumoniae. The vaccine also protected against the fungi Rhizopus delemar and Candida albicans, which also frequently affect hospitalized people.

Related: Cleaning product residues may be driving a deadly superbug's antibiotic resistance

Aluminum hydroxide and monophosphoryl lipid A are already used in vaccines and approved by regulatory agencies in both the U.S. and Europe, Spellberg said. Mannan, a component of fungal cell walls, is not yet an approved vaccine adjuvant, but it has been tested in humans in other medications without apparent safety issues, he said.

The research also found that the key reason the adjuvant-only vaccine worked was that it activated macrophages, immune cells that engulf and destroy foreign invaders. The researchers also observed other changes in the immune system, such as an increase in anti-inflammatory immune proteins called cytokines, and a decrease in pro-inflammatory cytokines. Though all the mechanisms aren't clear, this ratio has been linked to better survival after infection in previous studies, the researchers wrote. 

In mice, the vaccine's protection persisted for 28 days.

Giving this vaccine to patients upon hospitalization or before outpatient surgery could reduce the rate of hospital-borne infections and help combat the problem of antibiotic resistance, study co-author Jun Yan, a doctoral student in microbiology at the University of Southern California.

"By reducing the infection rate in the hospital, we're also reducing the new emergence of antibiotic resistance, because we can also reduce the use of antibiotics in hospitals," Yan told Live Science.

Human testing is the next step. Other vaccines, such as the live tuberculosis vaccine, have long been known to trigger an innate immune response in addition to raising the body's guard against specific germs, Henao Tamayo, who studies those vaccines, told Live Science. But getting a nonspecific vaccine approved by the Food and Drug Administration (FDA) is new territory, Spellberg said. The research team is currently in talks with the FDA about what kind of testing would be needed, and they hope to begin clinical trials in 12 to 18 months.

"I think what they have already developed is highly promising," Henao Tamayo said, "and we could learn a lot from human studies."

Measles cases, deaths and outbreaks jumped dramatically between 2021 and 2022, a new report from the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC) shows.

The research, published Friday (Nov. 17) in the CDC's Morbidity and Mortality Weekly Report (MMWR), revealed an 18% rise in the estimated number of measles cases between 2021 and 2022. That's an increase from about 7.8 million cases to 9.2 million. Measles deaths increased by 43% globally, from 95,000 in 2021 to 136,200 in 2022. The number of countries reporting "large or disruptive outbreaks" of measles jumped from 22 in 2021 to 37 in 2022, marking a 68% increase.

"The increase in measles outbreaks and deaths is staggering, but unfortunately, not unexpected given the declining vaccination rates we've seen in the past few years," John Vertefeuille, director of the CDC's Global Immunization Division, said in a statement.

"Measles cases anywhere pose a risk to all countries and communities where people are under-vaccinated," he said. "Urgent, targeted efforts are critical to prevent measles disease and deaths."

Related: Person who had measles 100 years ago helps scientists trace origins of virus

The WHO and UNICEF track the number of measles, mumps and rubella (MMR) vaccine doses administered worldwide each year and divide that number by the total population of children in the age group recommended to get the shot. Between 2000 and 2019, vaccine coverage with the first MMR dose rose from 72% to 86% worldwide. (One dose of the MMR vaccine is 93% protective against measles, while two doses are 97% protective.)

But in 2020, as the COVID-19 pandemic hit, coverage fell to 83%, and in 2021, it dropped to 81%, according to the MMWR. Global coverage increased to 83% in 2022 as some countries rebounded from pandemic setbacks, but in low-income countries, vaccination rates continued to fall.

From 2019 to 2021, "coverage in low-income countries fell from 71% to 67%, then to 66% in 2022," the MMWR states. Of 22 million children who missed their first MMR vaccine dose in 2022, more than half live in 10 countries: Angola, Brazil, the Democratic Republic of the Congo, Ethiopia, India, Indonesia, Madagascar, Nigeria, Pakistan and the Philippines.

"The lack of recovery in measles vaccine coverage in low-income countries following the pandemic is an alarm bell for action," Dr. Kate O'Brien, the WHO's director for immunization, vaccine and biologicals, said in the statement. "Children everywhere have the right to be protected by the lifesaving measles vaccine, no matter where they live."

Worldwide, coverage with the second MMR dose was 74% in 2022. Coverage with both the first and second doses needs to hit 95% to protect communities from outbreaks, according to the CDC.

Ever wonder why some people build muscle more easily than others or why freckles come out in the sun? Send us your questions about how the human body works to community@livescience.com with the subject line "Health Desk Q," and you may see your question answered on the website!

The world's first vaccine to protect against chikungunya virus, which is spread by mosquitoes, was just approved by the U.S. Food and Drug Administration (FDA).

"Infection with chikungunya virus can lead to severe disease and prolonged health problems, particularly for older adults and individuals with underlying medical conditions," Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, said in the agency's announcement.

The vaccine's approval, announced Thursday (Nov. 9), "addresses an unmet medical need and is an important advancement in the prevention of a potentially debilitating disease with limited treatment options," he said.

Chikungunya — which means "to become contorted" in Kimakonde, a language spoken by the Makonde people in Africa — most commonly causes fever and joint pain. It can also cause headache, muscle pain, joint swelling and rash. The joint pain can be severe but usually goes away in a few days. However, in some instances, that pain lingers for weeks, months or years.

Related: Should we kill every mosquito on Earth?

Rarely, chikungunya infections have caused eye, heart and neurological complications. And in rare cases, the virus can kill. Newborns infected around the time of birth, adults older than 65 years old and people with medical conditions, such as high blood pressure, diabetes or heart disease, face the highest risk of severe symptoms and death, according to the Centers for Disease Control and Prevention (CDC).

The new vaccine, called Ixchiq, is approved for use in people ages 18 and older "who are at increased risk of exposure to chikungunya virus," according to the FDA's approval. It's given as a single-dose injection into the muscle and contains a "live" but weakened version of the virus.

In trials, the most commonly reported side effects were headache, fatigue, muscle pain, joint pain, fever, nausea and tenderness. Notably, about 1.6% of people in the trials developed more severe, chikungunya-like symptoms that interfered with daily activities or required medical attention.

Because of these rare severe effects, "the FDA is requiring the company to conduct a postmarketing study to assess the serious risk of severe chikungunya-like adverse reactions following administration of Ixchiq." It's also not known whether the virus in the vaccine could pass through the placenta to a fetus and cause harm, so the vaccine's label states this in a warning.

Most cases of chikungunya occur in tropical and subtropical regions of Africa, Southeast Asia and parts of the Americas where mosquitoes that carry the virus are widespread, according to the FDA. Cases in the U.S. mostly occur in travelers who've just returned from places where the disease regularly spreads. Between 2014 and 2022, between 30 and 2,800 such travel-related cases were reported in the U.S. each year, CDC data shows.

In 2014 and 2015, though, 12 people in Florida and one in Texas caught chikungunya locally, and there have also been cases of local infection in Puerto Rico and the U.S. Virgin Islands. These states and territories harbor mosquito species that can carry the virus.

That said, no locally-acquired cases have been reported in either U.S. states or territories for the past three years (throughout the COVID-19 pandemic).

Modeling data do suggest chikungunya-carrying mosquitoes could spread to new territories in coming years due to climate change, so the viral disease could theoretically pose a problem in new places in the future.

Ever wonder why some people build muscle more easily than others or why freckles come out in the sun? Send us your questions about how the human body works to community@livescience.com with the subject line "Health Desk Q," and you may see your question answered on the website!

The Food and Drug Administration (FDA) has authorized a new formulation of the COVID-19 vaccine made by the Maryland-based pharmaceutical company Novavax, the agency announced Tuesday (Oct. 3). The newly updated "nanoparticle" vaccine joins the Pfizer and Moderna COVID-19 vaccines already cleared for use in the U.S.  

The Novavax shot now includes a spike protein — a pointy structure found on the virus's surface — from a version of the virus that is currently circulating, called XBB.1.5. The widespread subvariant branched off of the omicron family tree. Compared to its old formula, the new Novavax shot is expected to provide better protection against both XBB.1.5 and its close relatives that stem from the same branch. 

The shot has been authorized for use in people ages 12 and older.  

"Today's authorization provides an additional COVID-19 vaccine option that meets the FDA's standards for safety, effectiveness and manufacturing quality needed to support emergency use authorization," Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, said in the agency's announcement. "As we head into the fall season and transition into 2024, we strongly encourage those who are eligible to consider receiving an updated COVID-19 vaccine to provide better protection against currently circulating variants."

Related: Who should get the new COVID vaccines? What to know about the 2023-2024 shots 

Updated COVID-19 vaccines from Pfizer-BioNTech and Moderna were approved in September, but the Novavax shot is based on different technology. 

The Pfizer-BioNTech and Moderna shots contain mRNA, a genetic molecule that carries instructions for human cells to build the spike protein once the vaccine enters the body. In contrast, the Novavax vaccine contains nanoparticles made out of lab-made spike proteins — so the spike proteins are made by cells in a lab, rather than inside the human body. 

In addition, the Novavax shot contains an "adjuvant," a substance that revs up the immune system to mount a stronger response to the vaccine.

The FDA says that individuals who have previously been vaccinated for COVID-19 can get one dose of the updated Novavax shot, provided that their last shot was given at least two months ago. People who have never been vaccinated against COVID-19 can get two doses of Novavax, spaced three weeks apart. People with weakened immune systems can consider getting a second dose of the updated vaccine two months after their first.

Additional doses "may be administered at the discretion of the healthcare provider, taking into consideration the individual's clinical circumstances," the FDA noted.

The World Health Organization (WHO) has just recommended a second vaccine to prevent malaria in children, almost exactly two years after it recommended the world's first.

When given seasonally, the vaccine, called R21/Matrix-M or just Matrix-M, is as effective as the previously recommended vaccine, known as RTS,S or Mosquirix, Tedros Adhanom Ghebreyesus, the director-general of the WHO, said at a news conference on Monday (Oct. 2). In trials conducted in regions where malaria spread seasonally, three doses of Matrix-M cut the rate of symptomatic malaria in the following year by about 75%. 

An additional, fourth dose of vaccine given a year after the third dose carries that protection into the next malaria season, Tedros said.

"As a malaria researcher, I used to dream of the day when we would have a safe and effective vaccine against malaria. Now, we have two," he said. "Demand for the RTS,S vaccine far exceeds supply, so the R21 vaccine is a vital additional tool to protect more children faster, and to bring us closer to our vision of a malaria-free world."

Related: Should we kill every mosquito on Earth? 

GSK, the maker of the first malaria vaccine, can make 15 million doses a year, The Associated Press reported. That vaccine, called Mosquirix, is given in four doses. This newly-approved second vaccine, developed by Oxford University, is manufactured by The Serum Institute in India, which has said it can manufacture up to 200 million doses of the three-dose vaccine a year.

Matrix-M will cost between $2 and $4 US dollars a dose, Tedros said. The WHO will now have to give the vaccine a stamp of approval, called "prequalification," that will allow partners like UNICEF and the global vaccine alliance Gavi to buy the vaccines to distribute.

"The RTS,S vaccine will be rolled out in some African countries early next year, and the R21 vaccine is expected to become available to countries by the middle of next year," Tedros said.

Malaria is caused by a mosquito-spread parasite, and the Matrix-M vaccine works by triggering an immune response against one stage of that parasite's life cycle, according to Gavi. It's at this stage, called the "sporozoite" stage, that the parasite exits a mosquito and enters the human body. Matrix-M contains part of a protein secreted by the sporozoites; part of a hepatitis B virus, which revs up the immune system; and an additional ingredient called an "adjuvant" that boosts the response even further.

Together with Mosquirix, Matrix-M is expected to reduce the rate of severe disease and death caused by malaria. But because these vaccines don't stop the transmission of malaria, they must still be paired with additional safeguards, like bed nets and insecticides, The Associated Press reported. 

The shots alone cannot snuff out the disease.

There's now another way to protect newborns from respiratory syncytial virus, or RSV, the leading cause of hospitalization for infants in the U.S.

The tool is a new vaccine, called Abrysvo and made by Pfizer, which is given in late pregnancy to send protective antibodies across the placenta to the developing fetus. The vaccine was approved by the Food and Drug Administration (FDA) in August, and now, the Centers for Disease Control and Prevention (CDC) has officially recommended the shot.

In clinical trials in which the shot was given between weeks 32 and 36 of pregnancy, the shot reduced newborns' risk of lower respiratory tract disease — meaning lung infections — from RSV by about 57% in the first six months of life. It offered slightly more protection against severe infections, in particular, cutting the risk by 76.5% in babies' first six months.  

The CDC recommends giving the shot during and in preparation for RSV season, which runs from late fall to early spring. Those giving birth during RSV season should get one dose of the vaccine between weeks 32 and 36 of gestation. 

Related: When should you get a flu shot? What to know for the 2023-2024 flu season

"This is another new tool we can use this fall and winter to help protect lives," said Dr. Mandy Cohen, director of the CDC, said in the agency's statement. "I encourage parents to talk to their doctors about how to protect their little ones against serious RSV illness, using either a vaccine given during pregnancy, or an RSV immunization given to your baby after birth." 

Here, "immunization" refers to giving infants drugs that contain lab-made antibodies that protect against RSV. There is no RSV vaccine approved for use in babies, but there are several antibody drugs available for infants, as the FDA recently approved a new one. 

"Most infants will likely only need protection from either the maternal RSV vaccine or infant immunization, but not both," the CDC noted. 

Looking for more information about the new vaccine or antibody drug? Here's everything you need to know. 

This article is for informational purposes only and is not meant to offer medical advice.

Scientists have created a new type of vaccine that instead of activating the immune system, selectively suppresses it. The so-called inverse vaccine, which has only been tested in mice so far, could one day be used to treat autoimmune diseases, in which the immune system attacks the body, the researchers say. 

The vaccine was given to mice with a condition similar to multiple sclerosis, an autoimmune disease in which myelin sheaths, or the insulating coats around nerves in the brain and spinal cord, are systematically destroyed. The treatment reversed symptoms of the disease and restored the function of nerve cells. The findings were described in a study published Sept. 7 in the journal Nature Biomedical Engineering. 

The vaccine essentially works by getting the immune system to recognize nerves as "safe," rather than as foreign invaders that should be attacked. The method hasn't been tested in humans, but experts told Live Science that the results are exciting. 

Related: In a 1st, scientists use designer immune cells to send an autoimmune disease into remission

"The idea of inducing tolerance in autoimmunity has been around for a while," Nick Jones, an associate professor of biomedical sciences at Swansea University in Wales who was not involved in the research, told Live Science in an email. But although the concept isn't new, this study is exciting because it showed this approach worked to alleviate, at least temporarily, autoimmune disease, he added.

Normally, immune cells called T cells protect the body from invaders like viruses and diseased cells, such as those in cancerous tumors. They identify which cells to attack by binding to specific antigens, or molecules, that typically appear on the outside of a virus or cell. However, in autoimmune disease, T cells mistakenly target healthy cells in the body by going after "autoantigens," molecules found only on those normal cells.

How do you get the body to stop attacking itself? You teach it to leave those autoantigens alone — and the body has a way of teaching this tolerance.

This teaching is done by a special group of cells in the liver that present antigens to T cells and tell them that they're safe; the liver has these special cells because, while filtering blood, it must differentiate between dangerous foreign antigens (from bacteria) and safe ones (from cells from one's self and food). In the new study, the researchers hijacked this process to mark the body's cells as "safe" from T-cell attack. 

They induced a form of multiple sclerosis in mice, which caused T cells to attack a specific antigen found in myelin. To stop the attack, they then tagged this antigen with a special sugar, and those sugar-tagged antigens got ferried to the liver, where the tolerance-teaching cells picked them up. The liver cells then reprogrammed T cells to leave myelin alone as well as protect it, essentially removing myelin from the immune system's "hit list." 

Related: The virus behind 'mono' might trigger multiple sclerosis in some

Inverse vaccines like these are exciting for a number of reasons, experts told Live Science. 

Firstly, the vaccines would suppress one cell type in the immune system, unlike many standard therapies that exert their effects more broadly. "Most immune therapies for autoimmune diseases act in a general way and don't just target the disease-inducing T cells," Lucy Walker, a professor of immune regulation at University College London who was not involved in the research, told Live Science in an email. "Ideally, we'd want suppression to act in an antigen-specific way, so only the pathogenic T cells are targeted and others are left free to function." This means you could avoid side effects, such as the increased risk of infection associated with using standard immune-suppressing therapies, such as methotrexate. 

Vaccines also stimulate the formation of immunological memory, or the body's ability to remember infections so that it can better respond the next time it encounters the same invading microbes. "Current therapies for autoimmunity are really sort of broad immune suppressants and they work while you're taking them but when you stop taking them, they stop working," study senior author Jeffrey Hubbell, a  professor of tissue engineering at the University of Chicago, told Live Science. "The idea with the vaccine is that you develop memory of that therapy." 

However, although the results of the new study are promising, more work needs to be done to develop this technology into a treatment that can be feasibly used in humans, Walker said. For instance, the protective effects shown in the study only lasted a few weeks, so it is unclear how long they could last, especially in people. 

Another potential issue is that the immune system could regain its memory of the target antigen, which may mean a booster dose would be needed, as is the case for many regular vaccines. Hubbell said that this is something that clinical studies will have to investigate. 

Success in animal models also doesn't always translate to humans. 

"It's unlikely that a single approach will work in all humans with a particular disease because these diseases have more variation in the human population — in part, because people are genetically very different from each other, including for genes that are important in the immune system, so they respond differently," Dr. David Fox, a professor of internal medicine at the University of Michigan who was not involved in the research, told Live Science. 

Another tricky issue is that for each autoimmune disease, scientists will have to identify the specific autoantigen that the body is primed to attack, which Jones said could involve an "extensive amount of research." For some autoimmune conditions, such as psoriasis, there isn't a consensus on what the autoantigen is, Fox said, and in multiple sclerosis, for example, there are several autoantigens that are known to be targeted by the body's immune system. This may make it difficult to measure the benefit of treatment in humans, he said.

Nonetheless, this approach of using sugar-modified antigens to dampen an autoimmune response has already been shown to be both safe and effective in early clinical trials for celiac disease — an autoimmune condition that injures the small intestines when those affected eat gluten. A second trial is also currently assessing the safety of the approach for patients with multiple sclerosis. 

"It's a really exciting area of research," Walker said, although it's lagging behind other types of immunotherapy, such as Teplizumab, which was recently approved by the U.S. Food and Drug Administration to delay the onset of type 1 diabetes. Regardless, "I do think it's a promising area for the future," Walker said.

Like the annual flu shots, COVID-19 vaccines have been getting a yearly update each fall — and we're due for a new batch.

So who should get one this time around? What shots are approved for use, and when will they be available? 

Here's what you need to know about the 2023-2024 COVID-19 vaccines.

Related: When should you get a flu shot? What to know for the 2023-2024 flu season

Adults without health insurance and those whose plans don't cover all costs of vaccines can get COVID-19 shots at no cost through the CDC's Bridge Access Program. These free vaccines are available at state and local health departments, federally supported health centers and participating retail pharmacy chains, including CVS, Walgreens and eTrueNorth. To find local vaccine sites participating in the Bridge Access Program, enter your ZIP code at Vaccine.gov and then check the box that says "Participating in Bridge Access Program."

Children eligible for the Vaccines for Children program, such as those who are uninsured or Medicaid-ineligible, can get no-cost COVID-19 vaccines through providers enrolled in that program.

Flu shots for the United States' 2023-2024 influenza season are now available. But when's the best time to get the vaccine, and who should get one?

Here's a rundown of what you need to know about this season's flu vaccines.

Related: Could we ever eradicate the flu?

"Egg allergy alone necessitates no additional safety measures for influenza vaccination beyond those recommended for any recipient of any vaccine, regardless of severity of previous reaction to egg," the committee advised. All vaccines should be given in settings where allergic reactions can be recognized and treated quickly, according to the new guidance.

Respiratory syncytial virus, or RSV, is a common respiratory virus that spreads seasonally. A new drug and several vaccines that prevent the infection have recently come to market.

Here's what you need to know about the three vaccines and one injectable drug that were recently approved by the Food and Drug Administration (FDA) to fight RSV. 

Related: Who should get the new COVID vaccines? What to know about the 2023-2024 shots 

In addition to Beyfortus, an older antibody shot against RSV, called Synagis (generic name palivizumab), is available. It was first approved in 1998. However, only children at the highest risk of severe disease, not healthy children, should be given this drug, the CDC recommends.

"Palivizumab is limited to children under 24 months of age with certain conditions that place them at high risk for severe RSV disease," the CDC states. "It must be given once a month during RSV season."

For example, Synagis is recommended for premature babies, especially those with chronic lung disease, and infants with certain heart diseases. This limited usage is partly due to the drug's high cost and the fact that it requires at least one and up to five shots a month during RSV season.

Editor's note: This article was last updated on Aug. 6, 2024, after the CDC updated its guidance for which older people should get an RSV vaccine. It was originally published on Aug. 24, 2023. 

This article is for informational purposes only and is not meant to offer medical advice.    

Ever wonder why some people build muscle more easily than others, or why freckles come out in the sun? Send us your questions about how the human body works to community@livescience.com with the subject line "Health Desk Q," and you may see your question answered on the website!  

A respiratory syncytial virus (RSV) vaccine has just been approved for use in pregnant people that protects against dangerous infection in newborns. 

On Monday (Aug. 21), the Food and Drug Administration (FDA) announced the approval of Abrysvo, a vaccine made by Pfizer, for use in pregnant individuals. The shot had already been cleared for use in people ages 60 and up, but now, it can also be given in the third trimester of pregnancy, specifically between weeks 32 and 36 of gestation. 

The vaccine prompts the pregnant person's immune system to make protective antibodies that then pass to the fetus through the placenta. In addition, as with other vaccines given in pregnancy, the antibodies may also pass to newborns through normal breast milk and the nutrient-dense colostrum made just after birth. (Other vaccines recommended in pregnancy include the flu vaccine and Tdap vaccine for whooping cough, or pertussis.)  

"RSV is a common cause of illness in children, and infants are among those at highest risk for severe disease, which can lead to hospitalization," Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, said in the announcement. "This approval provides an option for healthcare providers and pregnant individuals to protect infants from this potentially life-threatening disease." 

Related: Having a baby: Stages of pregnancy by trimester

That said, now that the FDA has approved the shot, the public is still waiting on a Centers for Disease Control and Prevention (CDC) advisory committee to issue recommendations about who should get it. The CDC committee will likely meet in October, NBC reported.

In most people, RSV causes mild, cold-like illnesses that resolve without medical attention. But infants, young children and people older than 65 can develop severe disease and potentially die from the virus. 

The FDA approved two RSV vaccines for older people earlier this year — Abrysvo and another vaccine called Arexvy — as well as an RSV-preventing antibody drug for infants up to 8 months old. Now, the new vaccine given in pregnancy provides an additional way to protect newborns and young infants from the infection.

In a clinical trial, 3,500 pregnant people received Abrysvo and another 3,500 received a placebo injection. In the 90 days after birth, the vaccinated group's babies had a 81.8% lower chance of severe lower respiratory tract disease — meaning severe lung infections — from RSV than the unvaccinated group's babies. And 180 days after birth, the vaccinated group's rate of severe infection was still 69.4% lower.

In a subgroup of 1,500 people who got vaccinated between weeks 32 and 36 of pregnancy, the shot worked even better. Their babies had a 91.1% lower rate of severe infection within 90 days and a 76.5% lower rate within 180, compared with a placebo group injected in the same trimester. 

The most commonly reported side effects among the vaccinated people were pain at the injection site, headache, muscle pain and nausea. 

Although not as commonly reported, the safety studies for the vaccines found that, compared with controls, vaccinated people had a slightly higher rate of the pregnancy-related high blood pressure disorder preeclampsia, the FDA noted. The vaccinated group also had a slightly higher risk of preterm birth. 

With the data at hand, the researchers couldn't "establish or exclude a causal relationship between preterm birth and Abrysvo." For this reason, "the FDA is requiring the company to conduct postmarketing studies to assess the signal of serious risk of preterm birth and to assess hypertensive disorders of pregnancy, including pre-eclampsia."

Moderna's experimental respiratory syncytial virus (RSV) vaccine was about 84% effective at protecting older adults from lower respiratory tract disease in a late-stage trial, the drugmaker announced Tuesday (Jan. 17). 

Moderna has yet to release the full trial results, but based on the company's analyses, it plans to submit the vaccine for Food and Drug Administration approval "in the first half of 2023," the company announced. Separately, the same vaccine is also being tested in children in an ongoing early-stage trial, the statement notes.

RSV most often causes mild, cold-like illnesses, but it can cause severe disease in infants, young children with certain medical conditions, and adults ages 65 and older, especially those with weakened immune systems or chronic heart or lung disease, according to the Centers for Disease Control and Prevention. There is no approved vaccine to prevent RSV, although several pharmaceutical companies are in the midst of late-stage trials testing vaccines in these high-risk groups.

Like Moderna's COVID-19 vaccines, the company's RSV vaccine contains messenger RNA (mRNA), a genetic molecule that instructs the body's cells to build specific proteins. In this case, the mRNA contains the blueprints for an "F glycoprotein," which RSV uses to break into cells; these proteins are locked into the shape they adopt just before fusing to their cellular victims.

Related: New RSV vaccine given in pregnancy protects newborns from illness, Pfizer says 

Moderna's ongoing late-stage trial includes about 37,000 adults ages 60 and older in 22 countries, including the U.S. The newly released data highlights the 64 cases of lower respiratory tract disease — infections that affect the lungs and airways below the "voicebox" — that have occurred within this cohort so far. 

All of the cases involved at least two symptoms of lower respiratory tract disease, such as cough and fever, and of these, 55 occurred in the placebo group and nine occurred in the vaccinated group. 20 cases involved three or more symptoms; 17 cases were in the placebo group, and three were in the vaccinated group.

Based on these numbers, the vaccine was 83.7% effective against lower respiratory tract disease involving two or more symptoms and 82.4% effective against disease involving three or more symptoms. "The trial is ongoing, and additional efficacy analyses are planned as cases accrue, including for severe RSV," Moderna's statement reads.

No safety concerns arose in the trial; the most common side effects of vaccination were pain at the injection site, fatigue, headache, muscle aches and joint stiffness. "Safety and tolerability will continue to be followed in this ongoing study," the Moderna statement reads.

"Today's results represent an important step forward in preventing lower respiratory disease due to RSV in adults 60 years of age and older," Stéphane Bancel, Moderna's CEO, said in the statement. "We look forward to publishing the full data set and sharing the results at an upcoming infectious disease medical conference." 

This year's flu shots appear to be a "very good match" to the circulating influenza strains, health officials say. However, even though flu season got off to an unusually early start, vaccination rates, especially among adults, are lagging those seen this time last year. 

"I can tell you firsthand: This year's flu season is off to a rough start," Dr. Sandra Fryhofer, the board chair of the American Medical Association and an internist, told reporters during a news conference Monday (Dec. 5). "We've forgotten how bad the flu can be. But this year's season is a shout out that it can get really bad and it's here, so people need to get vaccinated."

According to the Centers for Disease Control and Prevention's (CDC) latest flu surveillance report, more than 19,500 patients with influenza were admitted to hospitals between Nov. 20 and Nov. 26, compared with roughly 11,200 people hospitalized the week prior. 

So far this season, 14 children have died of the flu, half of whom died between mid- and late-November.

Related: Which flu shot should I get?  

As of Nov. 19, about 154.1 million doses of flu vaccine had been administered in the U.S., the CDC reported. An estimated 40% of the country's children and adolescents ages 6 months to 17 years had gotten a flu shot as of that date — about the same fraction as had by the same date last season. However, adults seem to be lagging slightly: As of mid-November, 51.7 million doses had been given to adults, compared with 54.1 million by the same time last year, the CDC reported. 

Likewise, vaccination rates among vulnerable adults have been low compared with last season. For example, as of October, vaccinations among pregnant people were down 12% compared with the same time last year, and among people ages 65 and older, the rate was down about 3%, Dr. Rochelle Walensky, director of the CDC, told reporters Monday. These groups, children younger than 5, and people with heart disease, asthma, kidney disease and diabetes face the highest risk of complications and death from influenza.

It's not too late to get a flu vaccine, and real-time data suggest that this year's shots are protective against the circulating strains. "The good news is that it looks like it is a very good match," Walensky said.

This year's flu shots protect against four types of flu viruses: two influenza A and two influenza B viruses. According to data collected by public health laboratories, more than 99% of the circulating viruses are influenza A, with most being A(H3N2) and a minority being A(H1N1). So far, the strains circulating look similar to the ones included in the vaccine, which means the shots should effectively train the immune system to recognize the viruses, the CDC surveillance report states.

Because different flu strains could gain prominence later in the season, we won't know exactly how protective this season's shots are until early 2023, but in general, flu shots have historically been about 40% to 60% effective when they're a "good match." In this context, that means vaccinated individuals would be 40% to 60% less likely to visit the doctor for flu than people who aren't vaccinated. And although flu shots don't completely eliminate your chance of falling ill, when vaccinated individuals catch the flu, they have a lower chance of severe illness and death than unvaccinated people. 

You should still get a flu shot even if you've already caught influenza this season, because the shots may protect you against a different strain than the one you got. 

"The only thing worse than getting flu once in a season is getting it again" after being exposed to a different strain, Fryhofer said.

Editor's note: This page was last updated on Aug. 24, 2023 following the approval of various RSV vaccines and a new preventative, antibody-based drug. 

Respiratory syncytial virus, or RSV, is a very common respiratory virus, particularly among children. 

Indeed, "by age 2, 90% of people have had at least one infection" with RSV, said Dr. Octavio Ramilo, chief of infectious diseases at Nationwide Children's Hospital in Columbus, Ohio, who studies RSV. But people can catch the virus at any age, and become infected multiple times. 

In healthy children and adults, the virus typically causes mild, cold-like symptoms, but it can cause more serious disease in infants younger than 12 months old, or adults over age 65, according to the Centers for Disease Control and Prevention  (CDC). In these more serious cases, the virus spreads from the upper respiratory tract to the lungs, potentially leading to pneumonia, inflammation of the lungs' air sacs (alveoli), or bronchiolitis, inflammation of the lungs' small airway passages.

Infants are particularly at risk for severe disease because of their tiny airways — which, when inflamed, can easily compromise breathing — as well as their immature immune system, Ramilo said. 

"When you look at the number one cause of hospitalization in the first year of life, the number one is RSV," Ramilo told Live Science. It's a "very problematic pathogen," Ramilo added, and the infection leads to millions of doctor visits and thousands of hospitalizations each year.

Related: The deadliest viruses in history

What are the symptoms of RSV?

Symptoms of RSV often resemble those of the common cold. According to the CDC, typical symptoms include:

•  Runny nose/congestion 
•  Coughing 
•  Sneezing 
•  Fever 
•  Decrease in appetite 
•  Headache 

In infants, additional symptoms can include fussiness and poor feeding, according to the American Academy of Pediatrics (AAP).

Symptoms typically appear within four to six days of exposure to the virus, according to the Mayo Clinic. In severe cases, the Mayo Clinic says symptoms can also include:

•  Wheezing 
•  Difficulty breathing or rapid breathing 
•  A bluish color of the skin caused by lack of oxygen 
•  Severe cough 

People should seek immediate medical care if they experience difficulty breathing, a high fever or a blueish color of the skin, according to the Mayo Clinic. 

How does RSV spread?

RSV can spread through the air when an infected person coughs or sneezes, or through contact with contaminated surfaces. The virus can survive for up to six hours on hard surfaces, such as toys and doorknobs, and can survive for about 30 minutes on unclean hands, according to AAP. 

Children often spread the virus to others at school or in daycare settings, according to the CDC. Those who are infected with the virus are typically contagious for three to eight days; but people with an immunodeficiency may be contagious for much longer, up to four weeks and even after symptoms clear up.

Is RSV seasonal?

In the U.S., RSV typically circulates from late fall to early spring, but the exact timing in a given region can vary from year to year, according to the CDC. 

The COVID-19 pandemic also disrupted the timing of RSV season, leading to unusual summer outbreaks and earlier-than-average seasons. According to a report published in July 2021 in the CDC journal Morbidity and Mortality Weekly Report, RSV activity in the U.S. dropped to historically low levels from about April 2020 to April 2021. But when COVID-19 restrictions began to lift in the spring of 2021, RSV surged, leading to a summer spike in RSV infections, the report said.

The reason behind these trends still isn't clear, Ramilo said. Although some experts suspect that measures to reduce the spread of COVID-19 taken in 2020, such as mask-wearing and social distancing, also reduced the spread of RSV, Ramilo said he doesn't think this is the whole story. "I don't think we can explain everything from nonpharmaceutical interventions" like masking wearing and social distancing, said Ramilo, who noted that other respiratory viruses, such as rhinovirus and adenovirus, still circulated in 2020, despite restrictions. 

What is clear is that the summer of 2021 saw a dramatic increase in RSV hospitalizations. "Here, we saw a big increase in July and August," at the same level that's usually seen in December or January, Ramilo said. In 25 years of studying RSV, "this is the first time we've seen an outbreak in the middle of July and August," he said.

Related: 20 of the worst epidemics and pandemics in history

Is RSV the same as COVID-19?

RSV is different from COVID-19. RSV belongs to a family of viruses known as pneumoviruses, whereas SARS-CoV-2, the virus that causes COVID-19, belongs to a group of viruses known as coronaviruses. Since RSV and SARS-CoV-2 are both respiratory viruses, their symptoms can be similar, according to the Mayo Clinic.

It is possible to be infected with both RSV and COVID-19, but such coinfections do not appear to be common, Ramilo said. Doctors have been on the lookout for these coinfections because it's known that children can sometimes be infected with RSV and other coronaviruses that cause the common cold, Ramilo said. But "we haven't seen very many cases [of RSV and COVID-19 coinfections], just a handful," he said.

What are the risk factors for RSV?

According to the CDC and AAP, people at risk for severe RSV infections include:

•  Premature babies, particularly those born before 29 weeks 
•  Children younger than 2 years old with congenital heart disease or chronic lung disease 
•  Children or adults with weakened immune systems due to a medical condition (such as cancer) or medical treatment (such as an organ transplant) 
•  Adults older than 65, especially those with chronic heart or lung disease 

Every year in the U.S., the virus leads to approximately 2.1 million doctor's visits among children younger than 5 and about 58,000 to 80,000 hospitalizations in the same age group, the CDC estimates. It's the most common cause of hospitalization in infants, and annually, 100 to 300 children under 5 die from the infection in the U.S.

Among adults ages 65 and older, RSV leads to 60,000 to 160,000 hospitalizations each year and about 6,000 to 10,000 deaths in the U.S.

 Related: 28 devastating infectious diseases 

How is RSV treated?

There's no specific treatment for RSV. Because RSV is caused by a virus, not a bacterium, antibiotics won't work to treat the infection. Most people who catch RSV get better within a week or two without medical intervention.

Over-the-counter medicines, such as acetaminophen or ibuprofen, can help manage symptoms, such as pain and fever. Children should never take aspirin, according to the CDC. People can also use nasal saline drops and suctioning to help with a stuffy nose, according to the Mayo Clinic. Those with an infection should drink plenty of fluids to stay hydrated. 

RSV may also increase the risk of ear infections in children, according to the AAP. If a child develops a bacterial ear infection, their doctor may prescribe antibiotics.

In rare cases, people with RSV are hospitalized, and their treatment in the hospital may include fluids, additional oxygen or use of a mechanical ventilator to help with breathing.

In the U.S., about 3% of infants with RSV infection need to be hospitalized, Ramilo said. But most are able to go home within two to three days, according to the AAP. 

How to prevent RSV spread

Basic hygiene measures can reduce the risk of RSV infection, according to the Mayo Clinic, including:

•  Frequent hand washing 
•  Regular cleaning of frequently-touched surfaces, such as doorknobs, as well as children's toys 
•  Covering coughs and sneezes (with your sleeve rather than your hands.) 
•  Avoiding contact with sick people 

People who have cold symptoms should steer clear of those at risk for severe disease from RSV.

Is there a vaccine for RSV?

There are two FDA-approved vaccines for RSV — one for older adults, and one for both older adults and pregnant people. 

The FDA approved the first-ever RSV vaccine in May 2023. The shot, called Arexvy and made by the pharmaceutical company GSK, is approved for adults ages 60 and older.

The vaccine contains an adjuvant, a substance that revs up the immune system, and a lab-made version of a protein found on the surface of the virus. The virus uses this fusion, or "F" protein, to break into cells. The shot trains the immune system to recognize what the F protein looks like in its "prefusion" form, the shape it's in before it infects cells.

The second RSV vaccine approved by the FDA is called Abrysvo. Made by Pfizer, the shot was approved for older adults in May 2023 and for pregnant people in August 2023. Like Arexvy, Abrysvo contains lab-made perfusion F proteins. Neither vaccine contains preservatives, according to their drug labels.

Read more about the vaccines and who should get them.

Are there drugs to prevent RSV?

There are two antibody-based drugs available to protect infants and some young children from RSV.

These injectable drugs, called monoclonal antibodies, are given to infants during their first RSV season. And some older children at high risk of infection are recommended the shots in their second RSV season. 

The shots contains lab-made proteins that mimic antibodies made by the immune system. This type of drug doesn't train a child's immune system to make its own RSV-fighting antibodies, like a vaccine would. Instead it provides a ready-made supply.

Read more about the monoclonal antibodies, who should get them and when. 

Additional resources

Read more about RSV in infants and children, from the American Academy of Pediatrics. Get more details on RSV symptoms and care, from the CDC. Find information on RSV risks and complications, from the Mayo Clinic. 

This article is for informational purposes only, and is not meant to offer medical advice.   

A new respiratory syncytial virus (RSV) vaccine shielded newborns from severe cases of the illness in the critical months just after birth, the drugmaker Pfizer announced Tuesday (Nov. 1). The one-dose vaccine was given to pregnant people in their second or third trimesters, which triggered production of protective antibodies that then passed through the placenta.

The company monitored infants in the trial for six months after birth and found that, in that time frame, the vaccine was 69.4% effective at preventing severe cases of RSV that would require medical attention. However, the shot's effectiveness was higher — around 81.8% — in the first three months of life. 

This drop-off in immunity follows a pattern seen with other vaccines given in pregnancy, such as those for tetanus and whooping cough, which was described in a 2021 report in the journal JAMA Pediatrics. In general, vaccine-induced antibodies fall rapidly in the first two months of life and then steadily dwindle over the following four to eight months.

Pfizer's positive trial results have not yet been peer-reviewed, but the company does plan to submit the data to a scientific journal, according to the statement. The drugmaker also plans to apply for approval from the U.S. Food and Drug Administration (FDA) by the end of 2022.

Related: How to get pregnant: Tips and facts to increase fertility 

RSV typically causes mild colds in healthy children and adults, but the virus can cause severe disease in infants younger than age 1 and adults older than age 65, according to the Centers for Disease Control and Prevention (CDC). The infection can migrate from the upper respiratory tract to the lungs, triggering inflammation in the lungs' air sacs (pneumonia) or the organs' small airway passages (bronchiolitis). This inflammation can easily compromise infants' breathing by restricting their tiny airways.

Approximately 58,000 to 80,000 U.S. children under age 5 are hospitalized for RSV each year, and about 100 to 300 children die of the infection, according to the CDC. This year's RSV season kicked off early and aggressively, and doctors have already seen a surge of cases in emergency rooms and pediatric intensive care units, NPR reported. 

"We're very hopeful everything can be done in time to vaccinate mothers before the next RSV season," Annaliesa Anderson, chief scientific officer of vaccine research and development at Pfizer, told The Washington Post. "We're about to come into a very heavy RSV season. We’re seeing hospitals filling up. Everyone appreciates the urgency that can really help to prevent this."

Pfizer's vaccine contains crystalized "F" proteins, which RSV viruses use to enter human cells. The shot carries two versions of the F protein, representing the two major subgroups of RSV: subgroups A and B. These proteins are locked into the shape they adopt just before they fuse to a cell. 

The recent trial included 7,400 pregnant individuals, age 49 and younger, who either received the RSV vaccine or a placebo shot in their late second to third trimester. The trial spanned 18 countries and began in June 2020, meaning it covered multiple RSV seasons in both hemispheres, according to Pfizer's statement. 

The statement also noted that the shots were "well-tolerated with no safety concerns for both the vaccinated individuals and their newborns." 

As the new maternal RSV shots move towards FDA approval, there's also been good news regarding an RSV vaccine for older adults. Pfizer announced similarly positive results from its late-stage trial in people ages 60 and older back in August.