A fly that deposits its parasitic, flesh-eating offspring inside cows has been detected in Texas for the first time in decades, the U.S. Department of Agriculture (USDA) reported Wednesday (June 3).

A second case in a cow in the same county was announced June 5, and two more cases — in a cow and dog — in other Texas counties were flagged on June 8. Another cow case was announced June 9, bringing the total to five.

Here's what to know about the New World screwworm (Cochliomyia hominivorax), a pest that was eradicated from the U.S. in the 1960s.

What is the New World screwworm?

New World screwworms are parasites that feed exclusively on the living flesh of warm-blooded animals, according to the American Society for Microbiology (ASM). The screwworms are the larvae, or maggots, of adult C. hominivorax flies.

The flies lay their eggs in animals' open wounds or body openings, such as the eyes, ears, nose, mouth or genitals. Once hatched, the maggots burrow into their host's flesh, using a screw-like motion that lends the species its name. The maggots have sharp mouth hooks that can cause extensive damage, deepening the wound and raising the chances of secondary infections. The infestation can be painful, cause swelling and bleeding, and can produce a foul smell.

After about a week of feeding, the maggots enter their next stage of development and exit the animal, burrowing into soil in order to "pupate" and mature into a fly.

Broadly, maggot infestations are known as myiasis, and myiasis caused by New World screwworms is a big problem for livestock agriculture. Across places where the fly species is endemic, or widespread, annual economic losses caused by the fly can amount to billions of dollars each year. The flies mostly infect large-hooved livestock, such as cows, sheep and horses. Less commonly, they can infect domestic dogs and wild mammals, such as deer, rabbits, opossums and birds.

Can the screwworm infect humans?

Yes, New World screwworms can sometimes infect humans, although it's fairly uncommon. The flies can potentially infect any warm-blooded animal, but livestock are most commonly affected.

People in endemic areas who work with livestock, have weakened immune systems, sleep outdoors, or have open wounds — however small — are most at risk for developing C. hominivorax infestations. As in animals, infestations in humans can be deadly, but they are treatable via physical removal of the maggots from the body.

Symptoms of infestation include feeling or seeing maggots move within a skin wound or sore, or in the ears, nose, eyes, or mouth; developing painful skin wounds or sores that worsen within a few days; bleeding from sores; and a foul-smelling odor at the site of the infestation.

The screwworms do not spread from infected animals to people or from person to person. Infestations start when a female fly lays eggs in a wound or bodily opening, like the eyes.

In 2025, the U.S. reported its first New World screwworm infection in a person in decades. That individual, in Maryland, had just returned to the U.S. after traveling to El Salvador, where the fly is endemic. That person recovered with treatment.

Can infected livestock be treated?

Yes, infected livestock with New World screwworms can be treated with antiparasitic medications. Treatment also involves physical removal of maggots from the flesh and disinfection of the wound sites. Treatment must be timely, as an infestation can kill livestock in 10 days, ASM notes.

Rather than culling whole herds — similar to what's done for commercial flocks infected with bird flu — affected farms are examined for additional cases and not allowed to move animals from the premises during that time, according to USDA. Infected animals are treated and quarantined until their wounds heal and they go a few weeks without any signs of reinfestation. Euthanasia for individual animals can sometimes be necessary if the infestation is too extensive.

If they meet all regulatory requirements, animals that have recovered from screwworm myiasis can enter the food supply, USDA says. Notably, screwworms do not infest dead meat, only healthy, living flesh. The screwworms thus pose a threat to food production but not to food safety.

Is it a big deal that it's been spotted in Texas?

Screwworm outbreaks can be incredibly costly if not snuffed out quickly — there's a reason the U.S. has poured so much effort into eradicating the pest. Experts estimate that, if a large outbreak took hold of the state today, the Texas economy could lose $1.8 billion due to disruptions to the livestock industry. Food prices would be expected to rise, in turn.

New World screwworms were declared eradicated from the continental U.S. in 1966, following an extensive effort that involved releasing sterilized male flies into the wild and breaking the species' reproductive cycle. Despite this local eradication, America still saw some major screwworm outbreaks due to flies and infected animals entering the country from Mexico. A 1972 outbreak was the worst recorded post-eradication, affecting multiple states and causing tens of thousands of cases in Texas alone.

A joint effort between the U.S. and Mexico was then established to prevent a similar outbreak from happening in the future, and the parasite had largely been eradicated in Mexico in the 1980s. But in recent years, there have been signs of a comeback. Cases have been moving northward from Central American countries, like Panama and Costa Rica, since 2023. In response, the U.S. has deployed a strategy, led by USDA, to drive cases back down.

"All models showed New World Screwworm entering the country in 2025," but these efforts likely bought the nation some time, USDA's June 3 statement notes.

So, the detection of C. hominivorax in a 3-week-old calf in Zavala County, Texas, was not necessarily surprising but it does require quick action. The case occurred in Southwest Texas about 50 miles (80 kilometers) from the U.S.-Mexico border. The maggots were seen around the calf's umbilical area. With treatment, the calf should recover, Agriculture Secretary Brooke Rollins told The Associated Press (AP).

"USDA urges residents to contact your veterinarian right away if you see any suspicious wounds, maggots, or infestations in your animals or herd," the agency said on X. "If you see signs of maggot infestations in live or very recently dead wild animals, especially in areas near the U.S./Mexico border, please call 866-4USDA-WS (866-487-3297) to report it to your local USDA Wildlife Services office."

The agency is now following strategies and actions outlined in the NWS Response Playbook to snuff out any potential danger in Texas. That includes establishing a quarantine zone around where the case was detected and limiting the movement of animals in that zone.

According to the AP, Rollins said the USDA is confident enough in its preparations that it believes "there is no threat of mass infestation." She added, "There is no reason to believe this incursion will result in establishment of the pest in our country."

Following the initial detection, USDA then detected a second screwworm case in Zavala County. The case was "within the established movement control zone and enhanced sterile insect dispersal area" that had been set up for the first case, Dudley Hoskins, Under Secretary for USDA's Marketing and Regulatory Programs, said in the June 5 statement.

On June 8, officials announced cases in a calf in La Salle County (just to the southeast of Zavala) and a dog in Andrews County (hundreds of miles northwest of Zavala), bringing the current total to four. Early reports indicate that the dog was recently in Mexico, hinting it may have caught screwworm there, but investigations are ongoing.

A case in another calf in La Salle County was reported June 9. Surveillance and response measures have been expanded in the area.

"While we address these instances that require immediate attention, and continue to sample suspected cases, we are simultaneously working to eradicate the pest entirely," Hoskins said in the June 8 statement. "We need the partnership of animal owners across the region — please stay vigilant, check your animals closely, and report anything that looks suspicious."

Editor's note: This story was updated June 9 with information about a fifth case. The article was first published June 4.

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

Anthropic's unveiling of its Claude Mythos Preview model alongside Project Glasswing is prompting widespread scrutiny ‪as experts warn that the artificial intelligence (AI) system's capabilities could accelerate the discovery and exploitation of software vulnerabilities.

Anthropic is keeping Mythos locked inside Project Glasswing ‪—‬ the company's attempt to contain and direct the model ‪—‬ thus limiting access to a small group of big tech companies focused on cybersecurity. Anthropic's decision not to release Mythos publicly has quickly fueled claims that the model is "too powerful" for wider use.

However, that containment has already come under pressure. Anthropic is investigating reports that a small group of users gained unauthorized access to the model through a third-party environment, raising fresh questions about how tightly systems like this can be controlled.

"Anthropic's Mythos Preview is a warning shot for the whole industry — and the fact that Anthropic themselves chose not to release it publicly tells you everything about the capability threshold we have now crossed," Camellia Chan, CEO and co-founder of X-PHY, a hardware-based cybersecurity company, told Live Science.

But what is Mythos really capable of, and can it be reined in?

What is Mythos, and what is it capable of?

Mythos is, by Anthropic's own description, its most capable model to date, with unusually strong performance in coding and long-context reasoning. In testing, that capability translated into real output ‪—‬ the model identified thousands of serious vulnerabilities across major operating systems and browsers, including flaws that had gone unnoticed for decades.

Mythos sits at the top of Anthropic's Claude models, but calling it an "update"' undersells its capabilities. Based on the information Anthropic representatives have shared and the details that have surfaced through leaks, the system is built to handle large, messy codebases without losing the thread halfway through.

Unlike earlier models, which often drop off mid-task, Mythos can read through software, flag the gaps, and turn those gaps into something usable. According to Anthropic representatives, Mythos can turn both newly discovered flaws and already-known vulnerabilities into working exploits, including against software for which the source code is unavailable.

The difference between Mythos and earlier models is that the new one doesn't stop. Whereas earlier AI models tend to stall or need a nudge, Mythos keeps working through the problem, testing and adjusting until it lands on an exploitation that works.

Anthropic has not shared much about how Mythos is built or its underlying architecture.. But what's clear is that the AI is not just producing answers to questions. It can work with code, run checks and then use those results to decide what to do next. That puts it closer to actually testing systems, rather than just analyzing them.

It marks a key shift from how earlier models behave. Instead of pointing out where something might break, it can try things, see what happens, and change its approach if it needs to. It also seems able to carry work across multiple steps without resetting each time; it picks up where it left off instead of starting from scratch.

That doesn't mean it is acting independently, but it does indicate it can get further through a task before a human needs to step in. Anthropic said the model performed so strongly on existing cybersecurity benchmarks that those benchmarks became less useful, prompting evaluation in more realistic, real-world scenarios.

How did scientists test Mythos?

In Anthropic scientists' own testing, the model identified vulnerabilities in modern browser environments and chained multiple flaws into working exploits, including attacks that escaped both browser and operating system sandboxes. In practice, that means linking smaller weaknesses that might be harmless on their own into something that can reach deeper into a system. Sandboxes are meant to keep software contained; breaking out of them lets code access parts of the system it shouldn’t.

"In one case, Mythos Preview wrote a web browser exploit that chained together four vulnerabilities, writing a complex JIT heap spray [a trick attackers use to smuggle malicious code into memory and then make the system run it] that escaped both renderer and OS sandboxes," the scientists said in the report released April 7.

"It autonomously obtained local privilege escalation exploits on Linux and other operating systems by exploiting subtle race conditions and KASLR-bypasses. And it autonomously wrote a remote code execution exploit on FreeBSD's NFS server that granted full root access to unauthenticated users by splitting a 20-gadget ROP chain over multiple packets."

In addition, Mythos could turn both newly discovered flaws and already-known vulnerabilities into working exploits, often on the first try, Anthropic representatives said. In some cases, human engineers without formal security training could use the model to produce those exploits.

The most worrying aspect of Mythos' capabilities, Chan said, is how earlier versions are said to have breached their sandbox and accessed external systems — raising doubts about how well the system can be contained.

Chan pointed directly to those concerns, telling Live Science that Mythos demonstrated "unsanctioned autonomous behavior."

"Once AI can produce working zero-day exploits at speed, organizations lose the breathing space they have traditionally relied on to detect, patch, and recover," Chan said.

Anthropic representatives said they could publicly describe only a fraction of the vulnerabilities in widely used software that the model had found, as most remained unpatched — making independent verification difficult.

What is Project Glasswing, and what does it mean for Mythos?

Project Glasswing is Anthropic's attempt to contain and direct Mythos' capabilities. Rather than releasing Mythos as a general-purpose model, the company is providing access through a controlled framework that brings together technology companies and security organizations. The stated aim is to use the model to identify and fix vulnerabilities in widely used software before they can be exploited.

This is not a one-off. AI companies are starting to hold back their most capable models and limit who gets access, especially where misuse is a real concern.

David Warburton, director of F5 Labs Threat Research, said this kind of collaboration is a positive step, but he cautioned that it sits within a wider landscape where state-backed cybercriminals are already investing heavily in offensive and defensive capabilities.

"What is changing meaningfully is the pace," he told Live Science, noting that advances in AI are accelerating both vulnerability discovery and exploitation.

Software vulnerabilities sit at the foundation of much of today's digital infrastructure, and the ability to find and exploit them quickly has always been a decisive advantage.

Ilkka Turunen, field chief technology officer at software company Sonatype, added that the industry has already been moving in that direction, with AI contributing to a rise in both code production and adversarial activity. "It's not uncommon now to see AI-generated malware," he said, adding that many current security findings are likely already AI-assisted.

What systems like Mythos appear to do is compress the timeline further. Vulnerabilities can be identified, tested and weaponized more quickly, thus reducing the window between discovery and exploitation. Turunen said this means that "timelines to exploitation will continue to compress, new vulnerabilities will be discovered and spread faster, and attacks will continue to be completely autonomous."

Is Mythos really "too powerful to release"?

The idea that Mythos is "too powerful" to release caught on quickly following its launch, but it's not that simple, the experts who Live Science consulted said.

There are obvious risks. A system that can generate working exploits at speed lowers the barrier to attackers and makes it easier to exploit vulnerabilities at scale. That risk is not theoretical. Anthropic's own testing suggests the model can already do this reliably and at volume. The pieces themselves are not new. What stands out is that they are all in one place, working together. That makes the whole process faster and easier to run in an end-to-end fashion.

Chan argued that focusing on software-based controls alone will not be enough to address that shift. "The industry keeps making the same mistake: relying on software layers to solve problems created within the software layer," she said, adding that stronger protections at the hardware level are needed to prevent systems from being fully compromised.

The longer-term impact of Mythos is likely to depend less on the model itself and more on how quickly similar capabilities become widely available.

Warburton warned that the risk is not a single dramatic incident but a gradual change in how digital systems are trusted and used. "We're already seeing early signs of an internet increasingly shaped by automation," he said, pointing to a growing volume of machine-generated content and activity.

If systems like Mythos accelerate that trend, the result could be an environment where both legitimate activity and malicious behavior are increasingly driven by automated processes, making it harder to distinguish the two, Warburton warned. At the same time, the abundance of vulnerabilities being discovered in key systems we use every day may outpace the ability to fix them, especially if we start to see similar AI models becoming more widely available.

Anthropic's decision to keep Mythos within the confines of Glasswing places it in a controlled setting. Whether that remains the case will depend on how quickly comparable systems emerge elsewhere and how effectively the cybersecurity industry adapts to a world in which the time between a vulnerability's emergence and exploitation continues to shrink.

Florida is experiencing its most intense drought in 15 years, with more than 70% of the Sunshine State facing what the U.S. Drought Monitor calls "extreme" to "exceptional" drought conditions.

Northern Florida is suffering the driest conditions in the state, and recent rainfall has brought almost no relief, according to the latest drought data. Forecasts show no rain and high temperatures over the next week, so the situation will likely get worse before it gets better, experts told Live Science.

"Dry conditions have been building throughout the winter," Esther Mullens, an assistant professor of geography at the University of Florida, told Live Science in an email. "Three months ago, 98% of the state was in unusually dry conditions, however only 4% were in severe to exceptional drought. As of currently, this number has risen to over 71% in severe to exceptional drought."

Here's everything you need to know about Florida's drought, including how it got to this point, how long it will last, and what the impacts will be.

Why is Florida in a drought?

Florida, along with Georgia and other parts of the U.S. Southeast, currently sits beneath a ridge of high atmospheric pressure that has moved in and out of the region since fall last year but remained stationary since March. This means the air above the Southeast is sinking and compressing, which reduces humidity and prevents cloud formation.

"Rain cannot form in sinking air so it just stays warm and dry," Pam Knox, an agricultural climatologist at the University of Georgia and the director of the Georgia Weather Network, told Live Science in an email.

Clear skies have dominated for weeks over Florida and other parts of the Southeast. But it's not just high pressure that's driving the current drought, because rainfall has been below average for months. Florida was unusually dry for much of last year, and many areas have received less than 50% of their normal rainfall since Sept. 1, 2025, according to the National Weather Service.

"That means they are about 20 to 25 inches [50 to 65 centimeters] below what would be considered average rainfall," Knox said.

Months of dry weather were followed by a La Niña winter, which shifted the jet stream northward. This brought colder, wetter conditions to the northern U.S. and Canada, while the southern U.S. became warmer and drier.

"The combined effects of the lack of tropical storms last year with the La Nina over the winter, which is usually a time of warmer and drier climate than average, have helped lead to this current situation," Knox said.

Why is the current Florida drought so bad?

The current drought in Florida differs from previous bad droughts because it has hit in spring instead of summer. The last time the U.S. Drought Monitor recorded such exceptionally dry conditions in the Sunshine State was June 2011, but it has not been this dry so early in the year since 2000, Knox said.

While the La Niña, low precipitation, and fewer storms this season are attributable to natural variability, global warming and shifts in the water cycle caused by higher temperatures may be contributing to the dryness, Knox said.

The impact of climate change is difficult to disentangle from natural variation without proper attribution studies, Mullens agreed.

How long will the Florida drought last?

Current drought conditions in Florida will probably worsen until the end of April, but they are expected to improve slightly in May as the high-pressure area in the atmosphere moves away from the Southeast.

"In the Southeast, the worst drought is in northern Florida and southern Georgia, but other areas are likely to get worse over the next couple of weeks with high temperatures and no rain in the forecast," Knox said. "We expect the weather pattern to change around the end of the month as the high pressure shrinks off to the east, which will allow cold fronts that could produce rain to enter the Southeast again."

It's unclear how conditions will evolve through summer, but a lot of moisture will be needed to end the drought. Ideally, a tropical storm or a stationary front should bring enough rain in the coming weeks to quench plants and replenish soil moisture.

"It is difficult to get out of drought in summer because the plants and evaporation tend to use every bit of rain that falls," Knox said.

A strong El Niño is on the horizon, which could bring wetter weather this summer, Mullens said. But a clear picture of this year's drought will emerge only once it's over, when scientists will be able to more accurately compare its length with droughts that struck Florida in 2000 and 2011.

What are the impacts?

Satellite data shows that shallow groundwater aquifers have dried up across the U.S. Southeast during this year's drought. That's because more water has been extracted from these aquifers than usual to irrigate farmland and provide drinking water for people under exceptionally dry conditions.

In Florida, aquifers are especially dry in the northern and central regions. Aquifers do not immediately recover from drought, because rainfall first has to wet the entire soil column before it can trickle down to replenish groundwater stores.

"Aquifers are considered to be a lagging indicator of drought because they get worse after the drought is bad at the surface and it takes them longer to recover," Knox said.

The drought has been felt across Florida, with some water districts imposing restrictions on water use for certain activities such as lawn irrigation. Dry vegetation has also provided ample fuel for wildfires, including a blaze in February in Big Cypress National Preserve, about 25 miles (40 kilometers) east of Naples. And even the Everglades are facing unusually dry conditions, news reports show.

If the drought lasts much longer, there will be more wildfires and possibly even water shortages, Knox said.

It might take several weeks of consistent rain or a tropical storm lasting multiple days to recover from this drought. Ideally, precipitation should be abundant but not come all at once; soils have limits on how much water they can absorb, and the surplus would likely run off, Knox said.

"Florida soils are generally pretty sandy so if it is really dry, they could probably absorb 2 [to] 3 inches [5 to 8 cm] easily over a few hours," she said. "Other areas in the Southeast with more clay soil would not be able to absorb as much."

Farmers, in particular, are desperate for rain. "In all my years of farming, I've never personally experienced a spring this dry," Shannon Nixon, a soybean and peanut farmer near Baker, Florida, told Farm Progress. "To be this dry this early in the spring is very concerning."

The drought may take a huge toll on farmers' income, as many have likely delayed planting crops or decided not to plant crops at all for fear of them dying, Knox said. And if these dry conditions persist, consumers will also be affected, because food production will decrease locally and some of it will not be made up by imports.

"That will mean shortages of some products that are produced locally like vegetables," Knox said.

Most of the rechargeable batteries used in today’s technology, from electric cars to the phones in our pockets, are lithium-ion (Li-ion) batteries. Since its inception in the early 1990s, Li-ion battery technology has been widely adopted for its high energy density, lightweight construction and ability to provide high voltage on demand for gadgets and vehicles alike.

But scientists are working on a new contender that threatens to relegate Li-ion to the past — at least in specific applications. Sodium-ion (Na-ion) batteries (sometimes called NIBs as an abbreviation of Na-ion battery) are an emerging battery technology that stores charged sodium ions in batteries’ electrodes, rather than lithium ions as in Li-ion batteries.

This is a hot area of research because it could unlock battery abundance, with sodium far easier to source or produce than the critical mineral lithium, which is only found in small deposits around the world.

Na-ion batteries also come with inherent safety benefits that could make them more palatable for large-scale, static battery setups, scientists that are working on the technology say.

Na-ion batteries vs Li-ion batteries: What are the benefits?

The main benefit of Na-ion batteries is that they are cheaper, easier and more sustainable to manufacture because of the sheer availability of sodium.

“Particularly, sodium is cheaper, more abundant and less geographically concentrated than lithium,” explained Dustin Bauer, an associate at intellectual property firm Reddie & Grose with doctoral experience studying the synthesis, composition, and use of Na-ion batteries and Li-ion batteries.

With the past decade having made the potential pitfalls of the global supply chain plain to see, as well as climate targets requiring a mass switch to electrified grids and transport wherever possible, there’s a clear benefit to adopting batteries that don’t rely on hard-to-source critical minerals to function.

“For reference, Sodium is the sixth most common element on Earth, and has a natural abundance of 2,360 mg/L, whereas Lithium, at number 32 in the list, has a natural abundance of 20 mg/L,” said Carmen M. López, principal scientist in the electrochemistry group at the National Physical Laboratory (NPL).

Once the supply chains for Na-ion batteries are operational at scale, they could help drive the costs far below Li-ion batteries, flooding the world market with more affordable energy storage options. For example CATL, the world’s largest battery manufacturer, recently commenced commercial production of Na-ion batteries for heavy vehicles.

Beyond the silicon used for the cathode in the battery, the chemistry of Na-ion batteries also circumvents the need for other costly components.

"Because of the operating voltage of the batteries, Li-ion requires the use of copper for the negative current collector, but copper is more expensive and weighs more than aluminum," López said.

She added that Na-ion batteries carry the potential for replacing organic electrolytes — used as the conducting medium for ions in Li-ion batteries — with aqueous electrolytes. This would make battery production more sustainable and cheaper still.

Battery chemistry also lies at the heart of safety claims surrounding Na-ion batteries. Thermal runaway — an exothermic chain reaction that can occur inside battery cells and cause them to catch fire — is less likely to occur in a Na-ion battery than a Li-ion battery.

This is because sodium ions are larger than lithium ions and therefore have greater “friction” — the result is that, in the event of damage that could lead to thermal runaway, they flow to the impact point at a rate which is unlikely to cause a rapid spike in temperature. Lithium ions, on the other hand, can flow quickly, causing overheating, the release of oxygen and ignition.

Finally, Na-ion batteries offer improved temperature resistance over Li-ion batteries, due to their low volatility and the reduced viscosity of the electrolyte. In short, this refers to the degradation of performance at low temperatures linked to the lower charge density of sodium ions compared to lithium ions, meaning that the ions continue to move freely even in low temperatures.

In a recent study published Dec. 12 in the journal Chinese Chemical Letters, scientists at Hunan First Normal University and Central South University found that Li-ion batteries could retain just 20% of their room temperature energy capacity when tested at -4 degrees Fahrenheit (-20 degrees Celsius). Na-ion batteries, the researchers noted, could offer better performance, subject to further testing.

Could Na-ion batteries be good for EVs?

The lower cost and increased safety of Na-ion batteries make them a suitable candidate for EV batteries. First and foremost, as the world increases its EV adoption — with 39 countries having passed 10% EV sales share as of 2025, according to the energy think-tank Ember — more sustainable and scalable supply chains for vehicle batteries will become necessary.

Once Na-ion production is achieved at scale, it could be highly regionalized, with factories in the majority of world regions capable of capturing or synthesizing the hard carbon that forms the backbone of the devices.

Additionally, the reduced chance of thermal runaway occurring within Na-ion batteries could increase the safety of EV batteries, which currently combust at a rate similar to that of gasoline and diesel fuels, according to National Car Charging data.

No technology is perfect, however, and we’re unlikely to see Na-ion batteries replace all Li-ion batteries any time soon. This is because the drawbacks of Na-ion make it a more situational alternative to the lithium-based batteries we know so well.

First and foremost, Na-ion batteries have lower energy density than Li-ion batteries. This is for the same reason that they have lower viscosity – sodium ions are simply larger than lithium ions, reducing the overall movement that can occur within the Na-ion battery’s electrolyte and translate to power.

The mass of sodium is also three times that of lithium, per the American Physical Society, which means you get less charge held per gram of Na-ion battery.

In practice, this adds up to Na-ion batteries being unable to compete with Li-ion for sheer quantity of energy held. The same data from the American Physical Society quoted the average energy density of Li-ion batteries as being in the range of 100-300 watt hours per kilogram. CATL’s first-generation Na-ion batteries, in contrast, achieved a figure of just 160 Wh/kg.

The inherently lower energy density of Na-ion batteries compared to Li-ion is a major stumbling block to using them for EVs, despite the potential safety benefits of doing so. Bauer described the issue of energy density as the "main and possibly decisive" drawback for Na-ion batteries, and it’s clear that researchers are working hard to overcome this challenge.

“There is a lot of debate in the battery community about this,” López told Live Science. "Due to the limitations in power and energy density, to power your typical electric vehicle, the size and weight of Na-ion batteries that will be needed will make them unsuitable for onboard deployment. The best chance in transportation would [be] in slow-charging infrastructure, and/or ultra-compact, short distance drive vehicles."

López added that the disadvantages of Na-ion’s lower energy density can’t quite be offset by its lower cost and weight due to its simpler, copper-light design. So for the moment, the economics of some Na-ion batteries just don’t add up.

All of this means Na-ion batteries are at present more suitable for static systems — and are therefore not the first choice for EV batteries. But this is far from a niche market.

Grid storage beckons

Indeed, one of the most promising use cases for Na-ion batteries, backed up by the experts to whom LiveScience spoke, is grid-scale energy storage such as battery energy storage systems (BESS).

These vast arrays of batteries are becoming increasingly important for the stability of national and regional grids, in particular for storing the intermittent energy production of renewables such as solar and wind farms for later use.

For example, the U.K. Parliament has examined the risk of thermal runaway for grid-scale BESS, citing the examples of fires at BESS sites linked to the process in both Liverpool and Essex.

But even with the lower upfront cost of Na-ion taken into account, energy density remains a downside for the technology when it comes to energy storage. For example, EV and battery giant BYD’s MC Cube-SIB ESS, its Na-ion BESS product, delivers an energy storage capacity of just 2.3 MWh in its 20-foot size configuration, as reported by Energy Storage News. This compares to around 6.4 MWh for BYD’s Li-ion offering in the same lineup.

Bauer pointed to the Baochi Storage Station in Yunnan as an example of both Li-ion and Na-ion being used to store renewable energy at scale. Some of the main reported benefits of the approach include faster discharge of batteries — six times faster than current battery models, according to the Global Times — and better resilience in weather conditions ranging from (-4 to 113 degrees F (-20 to 45 degrees C).

When will Na-ion batteries be commercially available?

While research into Na-ion is ongoing and new breakthroughs help improve the energy density of Na-ion batteries, this is a mature field of research with huge commercial potential. In fact, we’re already seeing manufacturers turning out products powered by Na-ion batteries.

"Commercial production is already happening, with early mass production capacity coming online," said Bauer.

“CATL, who are the world’s largest Li-ion battery manufacturer, in 2025 unveiled a Naxtra passenger EV NIB with an energy density of 175 Wh/kg, and Freevoy, a mixed ion (mixed NIB and LFP Li-ion) battery. More recently, CATL revealed Tianxing II, a "mass-produced" NIB for light commercial vehicles."

Despite this, López cautions that more real-world safety tests for Na-ion batteries must still be completed: "For example, will it be more desirable and practicable to deploy these batteries in urban vs remote environments? How do we adapt them to existing electricity infrastructure? Among other things to be considered," she said.

Over the past 5,000 years, East Africa has dried out. Now, new research finds that this change may be making the continent pull apart faster.

Faults in the East African Rift Zone have sped up since the levels of large lakes have dropped, according to research published in November in the journal Scientific Reports.

The findings highlight the two-way relationship between the climate and plate tectonics, said study senior author Christopher Scholz, a geologist, physicist and professor emeritus at Columbia University.

"Usually it is something we think about the other way around: Mountains build, and that changes the local or regional climate," Scholz told Live Science. "But it can work the other way around too."

Scholz and his colleagues conducted their research at Lake Turkana in Kenya, which is 155 miles (250 kilometers) long, 19 miles (30 km) wide, and up to 400 feet (120 meters) deep in places. That's nothing, however, compared with the level more than 5,000 years ago, when the lake was up to 500 feet (150 m) deeper.

That was during the African Humid Period, when much of Africa was wetter than it is today. In East Africa, this period persisted from about 9,600 years ago to 5,300 years ago, with drier conditions prevailing over the past 5,300 years. The researchers studied lake-bed sediments to determine ancient water levels and sediment flows into Lake Turkana. In the process, they noticed many small faults and the fingerprints of long-ago earthquakes in the sediments.

The tectonic plate that underlies Africa is pulling apart in eastern Africa and may one day split into two plates with an ocean between them. The deep, narrow lakes in the region — including Lake Turkana and nearby waterways, such as Lake Malawi in Tanzania and Mozambique —, are the result of this rifting process, which is creating a deep valley in the region.

Scholz and his team wanted to know if the changes in the lakes themselves were influencing this rifting process. Water matters to tectonics: When glaciers retreat, for example, the lifting of their weight actually causes the land beneath to spring up like rising bread — a process called isostatic rebound. Large amounts of water similarly press down on the crust beneath, potentially affecting processes like earthquakes.

The researchers found that after the end of the African Humid Period, the faults in Lake Turkana began to move faster, at an average rate of 0.007 inches (0.17 millimeters) of extra movement per year. In general, Africa is rifting apart at 0.25 inches (6.35 millimeters) per year.

Using computer simulations, the researchers figured out that this seismic speedup likely has two causes. One is that with less water pressing down on the crust, the faults have more freedom to move: Imagine a vise loosening around two slabs of wood. The other cause is more indirect. On an island in the south side of Lake Turkana is a volcano with an active magma chamber. The removal of water from the African Humid Period decompresses the mantle under this volcano, leading to more melting. That melt, in turn, moves into the volcano's magma chamber, inflating it and leading to more tectonic activity on nearby fault lines.

"We see enhanced faulting during this time interval, so more pronounced earthquakes are presumably prevalent in this broader region now compared to 8,000 years ago," Scholz said.

The researchers are now working on a project at Lake Malawi looking at water level changes going back 1.4 million years, hoping to get a better sense of how the climate affects the separation of continents.

"This information about these huge changes in water volumes in these lakes is a really important part of the story," Scholz said.

A pill version of the popular weight-management drug Wegovy has been approved by the Food and Drug Administration (FDA) and is now available through various pharmacies and telehealth services in the U.S.

The drug has been available by prescription as a once-weekly injection in the U.S. since 2021. Like the injection, the new Wegovy pill contains semaglutide, the same active ingredient as Ozempic. It works by mimicking a hormone in the body — glucagon-like peptide-1 (GLP-1) — that helps control appetite and blood sugar levels.

Both forms of Wegovy are approved to help adults with obesity — as well as adults who are overweight and have related health conditions, like high blood pressure — lose weight and keep it off, in combination with a reduced-calorie diet and increased physical activity. However, only the injectable version is approved for children 12 and up with obesity; the pill version is not yet cleared for that age group.

Here's what to know about the new Wegovy pill and who might benefit most from it.

Do semaglutide pills work as well as injections?

The main difference between the Wegovy pill and the injection is how the drug enters the bloodstream.

When semaglutide is injected under the skin, it is absorbed directly into the blood. When taken as a pill, however, the drug must first pass through the stomach and intestines, where some of its active ingredient is broken down by digestive enzymes before it can be absorbed through the gut lining and into the blood.

Because of this, "only a small fraction [of the pill] reaches the bloodstream," explained Dr. Chika Anekwe, obesity medicine clinical director of the Massachusetts General Hospital Weight Center and an instructor in medicine at Harvard Medical School. This is an expected difference between injected and oral medications, in general.

Although the pill exposes the digestive tract to more semaglutide than the injection would, its local effects on the gut are minor, Anekwe explained. That's because the "key effects still require absorption and systemic signaling," so they only kick in once the drug reaches the bloodstream, she said.

To make up for that digestive process, the pill version of Wegovy is taken at a much higher dose than the injectable form. The highest dose of the pill is 25 milligrams, compared with 2.4 milligrams for the weekly injection, Anekwe told Live Science in an email.

The pill also comes with strict instructions for when you should take it, Anekwe said. It should be taken on an empty stomach in the morning with a small amount of water, and patients must wait at least 30 minutes before eating, drinking or taking other medications, its drug label says. This ensures that the medication will be properly absorbed at the intended dose. The injectable version does not have these restrictions; it can be taken at any time of day and with no fasting required.

Dr. Priya Jaisinghani, an endocrinologist and obesity medicine specialist at NYU Langone Health, discussed the effectiveness of the two formulations during an Endocrine Society webinar about GLP-1 pills in December 2025.

So far, "there has been no long-term, head-to-head trial" that has compared the once-daily 25-mg pill with the once-weekly 2.4-mg injection in adults with obesity, Jaisinghani said. However, results from clinical trials that tested the drugs separately suggest the two versions lead to very similar weight loss when taken as instructed.

In the STEP-1 trial, a study of 2.4-mg injectable semaglutide, participants lost an average of about 14.4% of their body weight. In the OASIS 4 trial, a study of the 25-mg pill, participants lost an average of about 13.9% of their body weight. Jaisinghani said these results indicate that the pill and the injection "offered comparable efficacy for weight management."

Is the Wegovy pill as safe as the injection?

The trials also suggest that Wegovy pills and injectables have similar side effects.

"Oral and injectable Wegovy have very similar, predominantly gastrointestinal side effects," Anekwe said. These include nausea, diarrhea, vomiting and constipation, for example.

About three-quarters of Wegovy users experience mild-to-moderate gastrointestinal symptoms, Anekwe said. But for both forms of the drug, a minority of patients — around 7% to 10% — stop taking the medication because of these effects, according to trial data.

(Some real-world data suggest that a higher percentage of patients stop taking GLP-1s within a year of starting them, but that may be due to a mix of factors, including both side effects and medication cost.)

Who might benefit more from the pill or the injection?

Patients considering Wegovy may opt for the pill or injection for different reasons. For instance, "the pill may be better for someone who is averse to using injections," Anekwe said.

The pill version may also be more appealing to people who do not have reliable access to refrigeration, such as frequent travelers, she said. That's because the pill can be stored at room temperature, unlike the injection, which must be refrigerated. Generally, the Wegovy injectables should be kept between 36 and 46 degrees Fahrenheit (2 to 8 degrees Celsius). And if needed, the pens can be stored at 46 to 86 F (8 to 30 C) for up to 28 days, if their caps haven't been removed.

That said, the strict daily schedule of taking a pill on an empty stomach with restrictions on food timing may be challenging for some people to stick to. Those individuals may prefer the convenience of a once-weekly injection.

Cost and insurance coverage may also influence which version people choose. The pill may be better for someone who doesn't have insurance coverage because it has a lower out-of-pocket cost, Anekwe said.

And besides lifestyle factors and cost, there is another important difference that determines who can use each version: Unlike the injectable form of Wegovy, which is approved for adolescents ages 12 and older with obesity, the Wegovy pill is currently approved only for adults.

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

The online admonition to "touch grass" to soothe your emotional state may be backed by science — at least in lab mice.

A recent study finds that mice that live outside are less anxious than those that spend their days in safe, shoebox-sized cages. And that may highlight a fundamental flaw in laboratory research, including that used to test the safety and effectiveness of drugs eventually intended for people.

Medications that seem to work in lab mice don't necessarily work in human patients, and some scientists think that they might fail, in part, because of how bizarre and isolated laboratory life is for the rodents.

"Why is there that huge gap in results between the animal models in the labs and the real-life experiences when we test [many] drugs in humans?" said first study author Matthew Zipple, a postdoctoral researcher at Cornell University "We think much of this effect may be explained by this really artificial, standardized environment in which lab animals are kept."

The findings were published in December in the journal Current Biology.

Less anxious in the outdoors

Both wild mice and humans have rich social environments, and wild mice are constantly on the go, foraging, burrowing and facing risks, including the many predators that like to snack on them.

In comparison, lab mice sit in small cages with two or three same-sex siblings. There, food and water are delivered on a regular schedule. Studying medications in those mice may be akin to limiting research to prisoners in solitary confinement, Zipple told Live Science.

Zipple and his colleagues set out to compare the psychology of two groups of lab mice: a group that remained in a laboratory and a group that lived with other mice in an outdoor enclosure, complete with grass, dirt and exposure to the sky. They did so using a standard maze, called the "elevated plus maze," which has two enclosed arms and two open, catwalk-style arms.

On their first exposure to this maze under bright lab lights, lab mice typically explore the open arms, find them terrifying, and basically never venture out on them again. Instead, they remain in the comparatively safe, enclosed portion of the maze. This reaction is so consistent that researchers use the open arms to induce and measure anxiety in lab mice.

But mice living in a wild-type environment weren't freaked out by the open arms at all, Zipple and his team found. They spent just as much time exploring these areas on subsequent visits to the maze as they had the first time, all while under bright light.

Meanwhile, cage-dwelling mice that were sent to live outside also saw their maze anxiety evaporate; animals that already had demonstrated an apparent fear of the open arms and then spent a week outside subsequently spent twice as much time exploring the open arms compared with animals that kept living in cages.

The use of the standardized maze was a "very powerful way to show the limits of business as usual," said Andrea Graham, an evolutionary ecologist at Princeton University who was not involved in the research.

Caged mice have other key differences

Graham's lab has shown that mice that live in lab cages are also immunologically different from mice who live outside and encounter dirt, plants and large numbers of other mice. That matters, she said.

In one famous 2006 case, a medication called TGN1412 seemed to boost the immune system against leukemia in lab mice but caused a near-fatal immune reaction in the first six healthy human volunteers exposed to the drug. Subsequent research revealed that, in the lab mice, the medication activated immune cells that regulate and calm the immune response. However, in mice living in wild-type enclosures, the medication instead activated cells that ramp up the immune response to the point that the body attacked itself.

"If we restrict ourselves to only studying a couple of different genotypes [genetic profiles] of lab mouse in the same immunologically boring, psychologically boring environments, we're not going to really be able to study the full spectrum of human immune or nervous system response to the environment," Graham told Live Science.

Using wild-style enclosures requires some upfront cost and effort, and it also reduces the rigid control that's placed on study animals in order to limit confounding variables in experiments. As such, they pull biomedical scientists out of their comfort zone, Zipple said.

But adding in tests of these less-confined mice could save a lot of effort and money on the human trials side by pinpointing the medications that are most likely to translate from the lab to the clinic, the study authors argue. Zipple and his colleagues are now looking at ways that caged and wild-living mice age differently.

"The broader goal is to make a list of biomedically relevant behaviors, phenotypes [observable traits] and psychological traits that look the same in the lab and the field," he said, to help with the issue of translating results to humans. They also want to compile a "list of traits that look quite different," he said.

If it feels like everyone around you has come down with the flu, you're not imagining it.

As of Jan. 9, the U.S. Centers for Disease Control and Prevention (CDC) estimates that at least 15 million people have gotten sick with the flu this season. Of those, 180,000 have been hospitalized, and 7,400 people have died from flu so far, including 17 children.

These numbers make the current flu season one of the worst the U.S. has seen in decades. According to Syra Madad, an epidemiologist at the Harvard Belfer Center and chief biopreparedness officer at NYC Health + Hospitals, who publishes a weekly analysis of respiratory virus trends in her newsletter Critical Health Voices, the country is experiencing the highest number of flu cases in nearly 30 years.

At Phoenix Children's Hospital, flu cases have been high since mid-December 2025, said pediatric infectious disease specialist Dr. Monica Abdelnour.

"Although the CDC [currently] estimates this flu season to be of moderate severity, the rates we are seeing are similar to, and in some cases slightly higher than, those observed in the 2024-2025 season, which was deemed high-severity," she told Live Science in an email. "It remains possible this flu season may ultimately be categorized as high severity as well."

While the CDC reported a slight dip in the number of lab-confirmed flu cases in the first week of 2026, compared to the last week of 2025, Madad told Live Science that it's "too early to declare we are past the peak." Flu activity in the U.S. usually peaks sometime between December and February. The CDC also noted that the small drop in confirmed cases could be linked to expected decreases in doctor visits and testing during the holidays, not an actual drop in flu spread.

The CDC recommends prompt treatment for people with suspected flu symptoms who are at increased risk of serious flu complications, including pregnant women and people with chronic health conditions, such as asthma, lung disease, diabetes, or heart disease.

Madad said that flu antivirals are "underused" and reminds people at high risk of severe flu or who are caring for someone who is high risk to ask their doctors about antivirals shortly after they suspect an infection. The good news is that current data show subclade K is still responsive to the standard antiviral medications doctors use for influenza, she said.

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

On Dec. 16 2025, the Trump administration announced plans to dismantle the National Center for Atmospheric Research (NCAR) — one of the world's leading weather and climate research centers. In a statement to USA Today, Russell Vought, director of the White House Office of Management and Budget, said NCAR is "one of the largest sources of climate alarmism in the country."

But dismantling NCAR could seriously impact the nation's capacity to ensure public safety and its ability to protect economic stability, Holly Gilbert, the institute's interim deputy director, told Live Science. "The research we do here directly applies to protecting the public," she said.

The National Science Foundation (NSF) established NCAR in 1960 to shield human life and property from atmospheric and solar hazards. At its core, the center's research translates vast atmospheric data from satellites, aircraft and ground sensors into forecasts that can potentially save lives.

For example, taking a flight used to be a riskier endeavor. Pilots encounter an abundance of challenges — from turbulence and tornadoes to ice on wings and rapidly varying pockets of wind known as microbursts. But thanks in no small part to the research conducted at the NCAR, flying has become safer, helping pilots avoid these hazards: There hasn't been a single crash on a commercial airline caused by sudden, sharp changes in wind speed in more than 25 years.

But the center's impacts stretch well beyond aviation safety. NCAR models help forecast tornadoes, hurricanes, floods, extreme heat, drought and the potential for wildfires. "Whenever there has been an early warning, NCAR science and models have been part of bringing that warning to the people who need to hear it," Daniel Swain, a climate scientist at University of California Agriculture and Natural Resources, told Live Science.

Swain, a research partner of NCAR, also stressed that without these early warnings, people could lose their properties or die unnecessarily in weather-related disasters.

NCAR also partners with insurance and reinsurance industries to assess the risks these hazards pose to lives and property. "NCAR provides leading weather research that helps keep people safe and protect homes, businesses, and jobs," Nicole Austin, senior vice president and director of federal affairs at the Reinsurance Association of America, told Live Science in an email. "Its long-term studies of hail and wildfires, along with real-time weather data, help reduce damage and help communities recover faster after disasters."

One center, multiple impacts

NCAR's models currently save the national aviation system an estimated $27 million annually. For terrestrial disaster resilience, NCAR's WRF-Hydro system powers the National Water Model (NWM), which monitors flood risk for more than 2.7 million stream locations.

NCAR has also developed GPS dropsondes—packages of instruments, tethered to little parachutes, that measure atmospheric conditions. These dropsondes reduced hurricane track forecast errors by up to 30%. Modern economic analyses estimate that such improvements in forecast accuracy save the nation up to $2 billion per major storm by optimizing protective decisions and reducing unnecessary evacuations.

NCAR also engages with private entities such as The Weather Company, which operates key digital consumer brands like The Weather Channel and Weather Underground. "Our proprietary forecasting capabilities — which are vital to national safety and security, economic resiliency, and aviation efficiency — greatly benefit from the basic and applied science and technology produced at NCAR and widely used across the entire weather enterprise, including directly at The Weather Company," Peter Neilley, senior vice president of science and forecasting operations at The Weather Company, told Live Science in an email.

NCAR's models also forecast phenomena beyond the weather. Its Wildland Fire model simulates how wildfires create their own weather, giving first responders critical on-the-ground intelligence, while its Fire INventory from NCAR (FINN) model tracks toxic smoke transport, alerting health officials to air quality hazards thousands of miles downwind.

NCAR's High Altitude Observatory (HAO) also anticipates threats to U.S. infrastructure from events originating in space, such as geomagnetic storms. Predicting space weather is essential for safeguarding the nation's power grid, GPS satellites and communication networks from solar flares that can trigger widespread blackouts and equipment failure.

Greater than the sum of its parts

A statement from the NSF said it "is reviewing the structure of the research and observational capabilities" of NCAR and will "explore options to transfer stewardship" of several of its strategic projects "to concentrate on needs such as seasonal weather prediction, severe storms, and space weather."

But the unique value of NCAR lies in its capacity to treat Earth as a single system, where all the different components — the atmosphere, the oceans, the land and water — are connected to one another, Gilbert said. "Risks to public health and safety are inherently complex and multidisciplinary," she said, "which makes it important to have the expertise and capabilities in one organization to look at where the Earth systems come together."

Modeling the path of a catastrophic wildfire, for example, takes more than data around the fuel available and local wind patterns; it requires simultaneously tracking how heat from the fire creates its own violent, localized winds and determining how multi-year drought has desiccated the fuels. Understanding the public health impact also requires modeling how the resulting toxic smoke will travel. NCAR's expertise is unique because it ensures that the intertwined components of fire, air temperature, dry land, water availability and air quality are modeled simultaneously using shared tools and computational resources, Gilbert said.

The complexity and interconnectedness of these types of disasters means that splitting the center into multiple distributed research locations could have serious consequences, Swain said.

Different areas of research at NCAR used to be structurally siloed, but they've evolved to be more integrated and better suited to addressing complex environmental challenges, Swain said. To better understand weather, you have to understand it in the context of climate, he said. "Otherwise it is like being an emergency room doctor without access to 20% to 40% of a patient's health records."

Returning to siloing would be akin to disassembling the central operating system from a custom, high-performance car and distributing the components to three different mechanics. Each part might function individually, but the dismantling process would impact the ability to drive the vehicle at high speeds safely, Gilbert said.

In a similar vein, splitting up NCAR would hinder the capacity to predict highly complex, multi-hazard events.

"Looking at individual parts is not nearly as important as looking at this integrated system," Gilbert said. NCAR researchers look at the "whole" using established observation, modeling and computational resources and drawing on multiple partnerships established with industries and universities. "It would be so costly to pull these pieces apart," Gilbert added.

Heart disease is the leading cause of death in the United States.

Since researchers first established the link between diet, cholesterol and heart disease in the 1950s, risk for heart disease has been partly assessed based on a patient’s cholesterol levels, which can be routinely measured via blood work at the doctor’s office.

However, accumulating evidence over the past two decades demonstrates that a biomarker called C-reactive protein – which signals the presence of low-grade inflammation – is a better predictor of risk for heart disease than cholesterol.

As a result, in September 2025, the American College of Cardiology published new recommendations for universal screening of C-reactive protein levels in all patients, alongside measuring cholesterol levels.

What is C-reactive protein?

C-reactive protein is created by the liver in response to infections, tissue damage, chronic inflammatory states from conditions like autoimmune diseases, and metabolic disturbances like obesity and diabetes. Essentially, it is a marker of inflammation – meaning immune system activation – in the body.

C-reactive protein can be easily measured with blood work at the doctor’s office. A low C-reactive protein level – under 1 milligram per deciliter – signifies minimal inflammation in the body, which is protective against heart disease. An elevated C-reactive protein level of greater than 3 milligrams per deciliter, signifies increased levels of inflammation and thus increased risk for heart disease. About 52% of Americans have an elevated level of C-reactive protein in their blood.

Research shows that C-reactive protein is a better predictive marker for heart attacks and strokes than “bad,” or LDL cholesterol, short for low-density lipoprotein, as well as another commonly measured genetically inherited biomarker called lipoprotein(a). One study found that C-reactive protein can predict heart disease just as well as blood pressure can.

Why does inflammation matter in heart disease?

Inflammation plays a crucial role at every stage in the development and buildup of fatty plaque in the arteries, which causes a condition called atherosclerosis that can lead to heart attacks and strokes.

From the moment a blood vessel is damaged, be it from high blood sugar or cigarette smoke, immune cells immediately infiltrate the area. Those immune cells subsequently engulf cholesterol particles that are typically floating around in the blood stream to form a fatty plaque that resides in the wall of the vessel.

This process continues for decades until eventually, one day, immune mediators rupture the cap that encloses the plaque. This triggers the formation of a blood clot that obstructs blood flow, starves the surrounding tissues of oxygen and ultimately causes a heart attack or stroke.

Hence, cholesterol is only part of the story; it is, in fact, the immune system that facilitates each step in the processes that drive heart disease.

Can diet influence C-reactive protein levels?

Lifestyle can significantly influence the amount of C-reactive protein produced by the liver.

Numerous foods and nutrients have been shown to lower C-reactive protein levels, including dietary fiber from foods like beans, vegetables, nuts and seeds, as well as berries, olive oil, green tea, chia seeds and flaxseeds.

Weight loss and exercise can also reduce C-reactive protein levels.

Does cholesterol still matter for heart disease risk?

Though cholesterol may not be the most important predictor of risk for heart disease, it does remain highly relevant.

However, it’s not just the amount of cholesterol – or more specifically the amount of bad, or LDL, cholesterol – that matters. Two people with the same cholesterol level don’t necessarily have the same risk for heart disease. This is because risk is determined more so by the number of particles that the bad cholesterol is packaged into, as opposed to the total mass of bad cholesterol that’s floating around. More particles means higher risk.

That is why a blood test known as apolipoprotein B, which measures the number of cholesterol particles, is a better predictor of risk for heart disease than measurements of total amounts of bad cholesterol.

Like cholesterol and C-reactive protein, apolipoprotein B is also influenced by lifestyle factors like exercise, weight loss and diet. Nutrients like fiber, nuts and omega-3 fatty acids are associated with a decreased number of cholesterol particles, while increased sugar intake is associated with a larger number of cholesterol particles.

Furthermore, lipoprotein(a), a protein that lives in the wall surrounding cholesterol particles, is another marker that can predict heart disease more accurately than cholesterol levels. This is because the presence of lipoprotein(a) makes cholesterol particles sticky, so to speak, and thus more likely to get trapped in an atherosclerotic plaque.

However, unlike other risk factors, lipoprotein(a) levels are purely genetic, thus not influenced by lifestyle, and need only be measured once in a lifetime.

What’s the best way to prevent heart disease?

Ultimately, heart disease is the product of many risk factors and their interactions over a lifetime.

Therefore, preventing heart disease is way more complicated than simply eating a cholesterol-free diet, as once thought.

Knowing your LDL cholesterol level alongside your C-reactive protein, apolipoprotein B and lipoprotein (a) levels paints a comprehensive picture of risk that can hopefully help motivate long-term commitment to the fundamentals of heart disease prevention. These include eating well, exercising consistently, getting adequate sleep, managing stress productively, maintaining healthy weight and, if applicable, quitting smoking.

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

The rise of artificial intelligence (AI) has permeated our lives in ways that go beyond virtual assistants like Apple’s Siri and Amazon’s Alexa. Generative AI is not only disrupting how digital content is created but it's starting to influence how the internet serves us.

Greater access to large language models (LLMs) and AI tools has further fueled the dead internet conspiracy theory. This idea, posited in the early 2020s, suggested that the internet is actually dominated by AIs talking to and producing content for other AIs — with human-made and disseminated information a rarity.

When Live Science explored the theory, we concluded that this phenomenon has yet to emerge in the real world. But people now increasingly intermingle with bots — and one can never assume an online interaction is with another human.

Beyond this, low-quality content — ranging from articles and images, to videos and social media posts created by tools like Sora, ChatGPT and others — is leading to a rise in "AI slop." It can range from Instagram Reels showing videos of cats playing instruments or using weapons, to fake or fictional information being presented as news or fact. This has been fueled, in part, by a desire for more online content to drive clicks, draw attention to websites and raise their visibility in search engines.

"The challenge is that a combination of the drive towards search engine optimization [SEO] and playing to social media algorithms has led towards more content and less quality content. Content that's placed to leverage our attention economy (serving ads, etc.) has become the primary way information is served up," Adam Nemeroff, assistant provost for Innovations in Learning, Teaching, and Technology at Quinnipiac University in Connecticut, told Live Science. "AI slop and other AI-generated content is often filling those spaces now."

Mistrust of information on the internet is nothing new, with many false claims made by people with particular agendas, or simply a desire to cause disruption or outrage. But AI tools have accelerated the speed at which machine-generated information, images or data can spread.

SEO firm Graphite found in November 2024 that the number of AI-generated articles being published had surpassed the number of human-written articles. Although 86% of articles ranking in Google Search were still written by people, versus 14% by AI (with a similar split found in the information a chatbot served up), it still points to a rise in AI-made content. Citing a report that one in 10 of the fastest-growing YouTube channels shows AI-generated content only, Nemeroff added that AI slop is starting to negatively affect us.

"AI slop is actively displacing creators who make their livelihood from online content," he explained. "Publications like Clarkesworld magazine had to stop taking submissions entirely due to the flood of AI-generated writing, and even Wikipedia is dealing with AI-generated content that strains its community moderation system, putting a key information resource at risk."

While an increase in AI content gives people more to consume, it also erodes trust in information, especially as generative AI gets better at serving up images and videos that look real or information that seems human-made. As such, there could be a situation where a deeper mistrust in information, especially in media brands and news, leads to human-made content being seen as fake and AI-made.

"I always recommend assuming content is AI-generated and looking for evidence that it's not. It's also a great moment to pay for the media we expect and to support creators and outlets that have clear editorial and creative guidelines," said Nemeroff.

Trust versus the attention economy

There are two sides to AI-generated content when it comes to the lens of trust.

The first is AI spreading convincing information that requires an element of savvy thinking to check and not take at face value. But the open nature of the web means it’s always been easy for incorrect information to spread, whether accidentally or intentionally, and there’s long been a need to have a healthy scepticism or desire to cross-reference information before jumping to conclusions.

"Information literacy has always been core to the experience of using the web, and it's all the more important and nuanced now with the introduction of AI content and other misinformation," said Nemeroff.

The other side of AI-generated content is when it's deliberately used to suck in attention, even if its viewers can easily tell it’s fabricated. One example, as flagged by Nemeroff, is of images of a displaced child with a puppy in the aftermath of Hurricane Helene, which was used to spread political misinformation.

Although the images were quickly flagged as AI-made, they still provoked reactions, therefore fueling their impact. Even obviously AI-made content can be either weaponized for political motivations or used to capture the precious attention of people on the open web or within social media platforms.

"AI content that is brighter, louder and more engaging than reality, and which sucks in human attention like a vortex … creates a "Siren" effect where AI companions or entertainment feeds are more seductive than messy, friction-filled, and sometimes disappointing human interactions." Nell Watson, an IEEE member and AI ethics engineer at Singularity University, told Live Science.

While some AI content might look slick and engaging, it might represent a net negative for the way we use the internet, forcing us to question if what’s being viewed is real, and to deal with a flood of cheap, synthetic content.

"AI slop is the digital equivalent of plastic pollution in the ocean. It clogs the ecosystem, making it harder to navigate and degrading the experience for everyone. The immediate effect is authenticity fatigue," Watson explained. "Trust is fast becoming the most expensive currency online."

There’s a flipside to this. The rise of inauthentic content could be counterbalanced by people being drawn to content that’s explicitly human-made; we could see better-verified information and "artisanal" content created by real people. Whether that’s delivered by some form of watermark or locked off behind paywalls and in gated communities on Discord or other forums, has yet to be seen. It's down to how people react to AI slop, and their growing awareness of such content, that will determine the shape of content in the future and how it ultimately affects people, Nemeroff said.

"If people find slop and communicate that slop isn't acceptable, people's consumer behaviors will also change with that," he said. "This, combined with our broader media diet, will hopefully lead people to make changes to the nutrition of what they consume and how they approach it."

Less surfing, more sifting the web

AI-made content is only one part of how AI is changing the way that we use the internet. LLM-based agents already come built into the latest smartphones, for example. You'd also be hard-pressed to find anyone who hasn’t indirectly experienced generative AI, whether it was serving up information suggestions or offering the option to rework an email, generating an emoji or automatically editing a photo.

While Live Science’s publisher has strict rules on AI use (it certainly can't be used for writing or editing articles), some AI tools can help with mundane image-editing tasks, such as putting images on new backgrounds.

AI use, in other words, is inescapable in 2025. Depending on how we use it, it can influence how we communicate and socialize online — but more pertinently, it’s affecting how we seek and absorb information.

Google Search, for example, now has an AI overview serving up aggregated and disseminated information before external search results — something which a recently introduced AI Mode builds upon.

“We primarily used the internet via web addresses and search up to this moment. AI is the first innovation to disrupt that part of the cycle," Nemeroff adds. "AI chat tools are increasingly taking up internet queries that previously directed people to websites. Search engines that once handled questions and answers are now sharing that space with search-enabled chatbots and, more recently, AI agent browsers like Comet, Atlas, Dia, and others.”

On a surface level, this is changing the way people search and consume information. Even if someone types a query into a traditional search bar, it’s increasingly common that an AI-made summary will pop up rather than a list of websites from trusted sources.

"We are transitioning from an internet designed for human eyeballs to an internet designed for AI agents," Watson said. "There is a shift toward "Agentic workflows." Soon, you generally won't surf the web to book a flight or research a product yourself; your personal AI agent will negotiate with travel sites or summarize reviews for you. The web becomes a database for machines rather than a library for people."

There are two likely effects of this. The first is less human traffic to websites like Live Science, as AI agents scrape the information they feel a user wants — disrupting the advertising-led funding model of many websites.

"If an AI reads the website for you, you don't see the ads, which forces publishers to put up paywalls or block AI scrapers entirely, further fracturing the information ecosystem," said Watson. This fracturing could even see websites shutting down, given the already turbulent state of online media, further leading to a reduction in trusted sources of information.

The second is a situation where AI agents end up searching, ingesting and learning from AI-generated content.

"As the web fills with synthetic content — AI slop — future models train on that synthetic data, leading to a degradation of quality and a detachment from reality," Watson said. Slop or solid information, this all plays into the dead internet theory of machines interacting with other machines, rather than humans.

"Socially, this risks isolating us," Watson added. "If an AI companion is always available, always agrees with you, and never has a bad day, real human relationships feel exhausting by comparison. Information-seeking will shift from ’Googling’ — which relies on the user to filter truth from fiction — to relying on trusted AI curators. However, this centralises power; we are handing our critical thinking over to the algorithms that summarise the world for us."

It’s the end of the internet as we know it… and AI feels fine

Undoubtedly, the ways in which humans are using the internet, and the World Wide Web it supports, have been changed by AI. AI has affected every aspect of internet use in 2025, from how we search for information, to how content is generated and how we are served the information we asked for. Even if you choose to search the web without any AI tools, the information you see could have been produced or handled by some form of AI.

As we’re currently in the midst of this change, it’s hard to be clear on what exactly the internet will look like as the trend continues. When asked about whether AI could turn the internet into a "ghost town," Watson countered: "It won’t be so much a ghost town as a zombie apocalypse."

It’s hard not to be concerned by this damning assessment, whether you're a content creator directly affected by AI or simply an end user who’s getting tired of questioning information.

However, Nemeroff highlighted that we can learn from the rise of social media and its impact on the internet in the late 2000s. It serves as an example of the disruption and challenges that such platforms faced when it comes to the use and spread of information.

"Taking a few pages out of what we learned about social media, these technologies were not without harms, and we also did not anticipate a number of the issues that emerged at the beginning," he said. "There is a role for responsible regulation as part of that, which requires lawmakers to have an interest in regulating these tools and knowing how to regulate in an ongoing way."

When it comes to any new technology — self-driving cars being one example — regulation and lawmaking are often several steps behind the breakthroughs and adoption.

It’s also worth keeping in mind that while AI poses a challenge, the agentic tools it offers can also better surface information that might otherwise remain buried deep in search results or online archives — thereby helping uncover information from sources that might not have thrived in the age of SEO.

The way humans react to AI content on the internet will likely govern how it evolves, potentially bursting an AI bubble by retreating to human-only enclaves on the web or requiring a higher level of trust signals from both human- and AI-made content.

"We find ourselves in a really challenging moment with this," concluded Nemeroff. "Being familiar with the environment and knowing its presence there is a key point to both changing the incentives around this as well as communicating what we value to the platforms that distribute it. I think we will start to see more examples of showing the provenance of higher quality content and people investing in that."

What if a single blood test could determine whether you had one of 14 types of cancer?

That's the question posed by a study published in November in the journal Cancer. Conducted by researchers at the cancer detection-test company Exact Sciences, the paper models how cancer care for five million U.S. adults might be changed by easy access to blood tests designed to spot many cancers — known as multicancer early detection (MCED) liquid biopsy tests.

The study suggests the tests could save lives by catching cancer at earlier stages, when it's more easily treated. It predicted that, over a decade of use, MCEDs could reduce stage IV cancer diagnoses in the U.S. by 45%, compared to the current standard-of-care.

But for now, liquid biopsies that test for multiple cancers still have unacceptably high false-positive rates. And even when they don't, there aren't clear guidelines for how to integrate them into the standard-of-care. That means they aren't going to make their way into the clinic in the near term, experts told Live Science.

Before the transformative effect predicted by the Cancer paper can be borne out, doctors will need to figure out how to best use these tests in the clinic.

The pitch for liquid biopsy

The idea behind liquid biopsy tests is that they enable clinicians to look for cancer without going anywhere near the tumor itself, Dr. Carolina Reduzzi, an oncologist and director of the liquid-biopsy platform at Weill Cornell Medicine, told Live Science.

"It's like translating a tissue biopsy into the blood," said Reduzzi, who was not involved in the Cancer report. These tests can detect various signs of cancer, including individual circulating tumor cells (CTCs), chunks of tumor genetic material floating in the bloodstream, and even tiny fragments of tumor cells.

Because they do not direct tumor sampling, liquid biopsy tests are comparatively simpler and less invasive. Additionally, the hope is that if clinicians regularly repeat liquid biopsies, they could build up a picture of how a tumor changes in response to treatment.

If a patient's tumors contain many genetically distinct cells, tissue biopsies that only sample one portion of the tissue may provide a biased view of their disease, said Reduzzi. Liquid biopsy, in contrast, should provide a broader picture of a patient's cancer by making it easier to analyze cells from multiple tumor sites.

Which tests are in use now?

To date, the U.S. Food and Drug Administration (FDA) has approved five liquid biopsy diagnostic tests, each for single types of cancer. These tests have been validated via assays that compared their ability to detect signs of cancer against tests that sample tumor tissue.

No MCED tests are currently approved or available through routine clinical care, although some, like Exact's Cancerguard and GRAIL's Galleri, are available in the United States as "laboratory-developed tests" (LDTs). LDTs exist in a regulatory gray area in which they are not formally approved by the FDA but are available to patients through their clinicians or independent telemedicine providers.

Dr. Iseult Browne, a clinical oncologist based at the Royal Marsden Hospital in London and the U.K. Institute of Cancer Research, said that progress in Europe is patchier. The U.K.'s National Health Service is conducting a trial of Galleri based on data from 140,000 participants. That data will be released next year.

Browne and Reduzzi noted that inertia in the field of oncology could delay the further rollout of liquid biopsies. Oncologists have, for decades, built diagnostic and treatment plans based on data from tissue-biopsy analyses. Shaking these entrenched practices, even with data showing the utility of liquid biopsies, is difficult.

Even with single-cancer tests, Browne says that standardization is an issue. "Everyone is using a different assay," so making head-to-head comparisons to decide which test is best can be confusing. Different trials have been analyzing different markers of cancer, at various timepoints in disease progression, she said.

'Less optimistic' predictions

Ruth Etzioni, a biostatistician at Fred Hutch cancer center in Seattle, leads a multi-institute effort to review emerging cancer treatment and diagnostics. Similar to the Cancer report, Etzioni's team has modeled the impact of MCEDs and predicts that they would allow cancers to be detected at earlier stages.

However, she added, "our numbers are a little less optimistic."

The tests' helpfulness varies by cancer type, because it hinges on how long different cancers remain in each stage of progression. If a cancer lingers longer in stage I and II, then MCED tests would be well-placed to diagnose it early. But if a cancer rapidly progresses to stage IV, then the test will be less useful, Etzioni explained.

The question of how long different cancers stay in each stage is still a matter of debate. The "dwell times" used in the recent Cancer report leaned more optimistic, assuming that cancers would progress slowly enough for an annual MDEC test to make a difference.

Another reason MCED tests are not ready to replace existing diagnostics is that some analyses will always require a tissue biopsy, and current medical guidelines advise doctors to make some clinical decisions based on tumor-tissue samples.

"Immunotherapy is given in some cases based on how much your tumor has leukocytes [immune cells] infiltrating the tumor," Reduzzi said. "You cannot get that in the blood." All the researchers interviewed for this article agreed that a positive on a liquid biopsy test would need to be followed up with further testing before any cancer treatment was initiated.

So, multicancer tests may diagnose cancer earlier, but whether that early diagnosis will lead to lower death rates will depend on whether those confirmation tests happen quickly, Etzioni said. And those follow-up tests also have to be up to the task of identifying early-stage cancer, she noted.

Fixing false positives

Emerging MCEDs also have issues with false positives, Browne said. Early, non-peer reviewed data from the ongoing trial shows that Galleri was extremely good at identifying people without cancer — correctly identifying people without the disease 99.6% of the time. But meanwhile, roughly 40% of the patients that the test diagnosed with cancer were actually cancer-free.

This number of false positives puts unnecessary worry on the patient, said Browne, and each false positive could trigger follow-up tests that people would not have gotten otherwise. If scaled up to the millions of people at elevated risk of cancer, it would significantly burden any health system that adopted the tests.

To reduce false-positive rates, future studies will need to find more reliable signals of cancer to detect. Detecting information from other cell types, like immune cells, has been shown to improve test specificity. Improvements to laboratory standardization could also help cut the false-positive rate.

Browne hopes that liquid biopsy could someday help patients avoid the sapping side effects that were once unavoidable parts of cancer treatment. For instance, an ongoing trial at the Royal Marsden Hospital is assessing whether a test could identify breast cancer patients who don't need post-operative chemotherapy. The test enables the doctors to assess a patient's risk even after their tumor has been removed because it looks for tumor DNA in the blood.

Reduzzi believes that optimized multicancer tests — which would identify a large fraction of people who have cancer while having a low false-positive rate — will transform cancer diagnostics, and that such tests are on the horizon.

"I don't think we have a test that is there," she said. "But I think we will. With time."

Editor's note: This story was updated on Jan. 5, 2026, to clarify a comment from Dr. Iseult Browne and correct the name of the ongoing Galleri trial.

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

Exascale computing is the latest milestone in cutting-edge supercomputers — high-powered systems capable of processing calculations at speeds currently impossible using any other method.

Exascale supercomputers are computers that run at the exaflop scale. The prefix "exa" denotes 1 quintillion, which is 1 x 10¹⁸ — or a one with 18 zeroes after it. Flop stands for "Floating point operations per second," a type of calculation used to benchmark computers for comparison purposes.

This means that an exascale computer can process at least 1 quintillion floating-point operations every second. By comparison, most home computers operate in the teraflop range (generally around 5 teraflops), only processing around 5 trillion (5 x 10¹²) floating-point operations per second.

"An exaflop is a billion billion operations per second. You can solve problems at either a much larger scale, such as a whole planet simulation, or you can do it at a much higher granularity," Gerald Kleyn, vice president of HPC & AI customer solutions for HPE, told Live Science.

The more floating-point operations that a computer can process every second, the more powerful it is, enabling it to solve more calculations much quicker. Exascale computing is typically used for conducting complex simulations, such as meteorological weather forecasting, modelling new types of medicine and virtual testing of engine designs.

How many exascale computers are there, and what are they used for?

The first exascale computer, called Frontier, was launched by HPE in June 2022. It has a recorded operating speed of 1.102 exaflops. That speed has since been surpassed by the current leader El Capitan, which currently runs at 1.742 exaflops. There are currently two at the time of publication.

Exascale supercomputers were used during the COVID-19 pandemic to collect, process and analyze massive amounts of data. This enabled scientists to understand and model the virus’s genetic coding, while epidemiologists deployed the machines’ computing power to predict the disease’s spread across the population. These simulations were performed in a much shorter space of time than would have been possible using a high-performance office computer.

It is also worth noting that quantum computers are not the same as supercomputers. Instead of representing information using conventional bits, quantum computers tap into the quantum properties of qubits to solve problems too complex for any classical computer.

In order to work, exascale computing needs tens of thousands of advanced central processing units (CPUs) and graphical processing units (GPUs) to be packed into a space. The close proximity of the CPUs and GPUs is essential, as this reduces latency (the time it takes for data to be transmitted between components) within the system. While latency is typically measured in picoseconds, when billions of calculations are being simultaneously processed, these tiny delays can combine to slow the overall system.

"The interconnect (network) ties the compute nodes (consisting of CPUs and GPUs and memory) together," Pekka Manninen, the director of science and technology at CSC, told Live Science. "The software stack then enables harnessing the joint compute power of the nodes into a single computing task."

Despite their components being crammed in as tightly as possible, exascale computers are still colossal devices. The Frontier supercomputer, for instance, has 74 cabinets, each weighing approximately 3.5 tonnes, and takes over 7,300 square feet (680 square meters) – approximately half the size of a football field.

Why exascale computing is so challenging

Of course, packing so many components tightly together can cause problems. Computers typically require cooling to dissipate the waste heat, and the billions of calculations run by exascale computers every second can heat them up to potentially damaging temperatures.

"Bringing that many components together to operate as one thing is probably the most difficult path, because everything needs to function perfectly," Kleyn said. "As humans, we all know it's difficult enough just to get your family together for dinner, let alone getting 36,000 GPUs working together in synchronicity."

This means that heat management is vital in developing exascale supercomputers. Some use cold environments, such in the Arctic, to maintain ideal temperatures; while others use liquid water-cooling, racks of fans, or some combination of the two to keep temperatures low.

However, environmental control systems also add a further complication to the energy management challenge. Exascale computing requires massive amounts of energy due to the number of processors that need to be powered.

Although exascale computing consumes a lot of energy, it can provide energy savings to a project in the long run. For example, instead of iteratively developing, building and testing new designs, the computers can be used to virtually simulate a design in a comparatively short space of time.

Exascale computers are so highly prone to failure

Another issue facing exascale computing is reliability. The more components there are in a system, the more complex it becomes. The average home computer is expected to have some sort of failure within three years, but in exascale computing, the failure rate is measured in hours.

This short failure rate is due to exascale computing requiring tens of thousands of CPUs and GPUs — all of which operate at high capacity. Given the high demands simultaneously expected of all components, it becomes probable that at least one component will fail within hours.

Due to the failure rate of exascale computing, applications use checkpointing to save progress when processing a calculation, in case of system failure.

In order to mitigate the risk of failure and avoid unnecessary downtime, exascale computers use a diagnostic suite alongside monitoring systems. These systems provide continual oversight of the overall reliability of the system and identify components that are displaying signs of wear, flagging them for replacement before they cause outages.

"A diagnostic suite and a monitoring system shows us how the machine is working. We can drill into each individual component to see where it’s failing and have proactive alerts. Technicians are also constantly working on the machine, to replace failed components and keep it in an operational state," Kleyn said. "It takes a lot of tender loving care to keep these machines going."

The high operating speeds in exascale computing require specialist operating systems and applications in order to take full advantage of their processing power.

"We need to be able to parallelize the computational algorithm over millions of processing units, in a heterogeneous fashion (over nodes and within a node over the GPU or CPU cores)," Manninen. "Not all computing problems lend themselves to it. The communication between the different processes and threads needs to be orchestrated carefully; getting input and output implemented efficiently is challenging."

Because of the complexity of the simulations being performed, verification of results can also be challenging. Exascale computer results cannot be checked, or at least not in a short space of time, by conventional office computers. Instead, applications use predicted error bars, which project a rough estimate of what the expected results should be, with anything outside of these bars discounted.

Beyond exascale computing

According to Moore’s Law, it is expected that the number of transistors in an integrated circuit will double every two years. If this rate of development continues (and it’s a big if, as it cannot go on forever), we could expect zettascale — a one with 21 zeros after it — computing in approximately 10 years.

Exascale computing excels at simultaneously processing massive numbers of calculations in a very short space of time, while quantum computing is beginning to solve incredibly complex problems that conventional computing would struggle with. Although quantum computers are currently not as powerful as exascale computers, it is predicted that they will eventually outpace them.

One possible development could be an amalgamation of quantum computing and supercomputers. This hybrid quantum/classical supercomputer would combine the computing power of quantum computers with the high-speed processing of classical computing. Scientists have started this process already, adding a quantum computer to the Fugaku supercomputer in Japan.

"As we continue to shrink these things down and improve our cooling capabilities and make them less expensive, it's going to be an opportunity to solve problems that we couldn’t solve before," Kleyn said.

Two might be better than one: A new vaccine that targets the viruses behind seasonal flu and COVID-19 triggers a stronger immune response than flu and COVID shots given separately, trial data suggest.

The combination shot, dubbed mRNA-1083, is made by the pharmaceutical company Moderna. The promising results of the Phase 3 clinical trial of the vaccine were published May 7 in the journal JAMA. This late-stage trial included two groups of adults ages 50 and older who were given either the new vaccine or a combination of previously approved flu and COVID-19 vaccines.

The trial runners looked at the quantity of antibodies, or protective immune proteins, made in response to each vaccine regimen. Antibody levels correlate with how well a shot should protect against a disease and how long that protection might last. They do not provide direct data on how well a shot drives down infection rates in real life — but ethically, such real-world data is difficult to gather when effective vaccines against an illness already exist.

While the U.S. Food and Drug Administration (FDA) has not yet given mRNA-1083 a final stamp of approval, experts told Live Science that the trial results are largely positive. However, political factors could hinder the shot's approval, some say.

Why do we need a combination vaccine?

The U.S. Centers for Disease Control and Prevention (CDC) already recommends that people get both their annual flu and updated COVID-19 vaccines at the same time. But at the moment, that requires two separate shots to be given at the same appointment.

The combination vaccine would be "a one-stop shop," said Dr. Peter Chin-Hong, an infectious-disease doctor at the University of California, San Francisco (UCSF) who was not involved in the Moderna trial. "A lot of times, people are not excited about needles. I mean, who likes getting a shot?" he told Live Science. With the decline in vaccination rates in the United States, a combination vaccine offers more convenience and helps people get on top of their immunization, he said.

The idea of combining multiple immunizations into one shot is not new.

"It is a very commonly used strategy, especially in children," said Dr. Monica Gandhi, an infectious-disease doctor at UCSF who was not involved in the study. An example of this is the measles, mumps and rubella (MMR) vaccine, which is a combination of three vaccines in one shot.

What is in mRNA-1083?

The new mRNA-1083 vaccine is based on the same messenger RNA (mRNA) technology that Moderna used in its FDA-approved vaccine against SARS-CoV-2, the virus behind COVID-19. mRNA is a genetic molecule that relays instructions for cells to build different proteins.

The new COVID-flu shot combines the company's updated SARS-CoV-2 vaccine, called mRNA-1283, and its newly developed flu vaccine, mRNA-1010. As of yet, there is no FDA-approved flu shot that contains mRNA, so this could be the first.

The culprits behind seasonal flu are influenza A and B viruses, which can be further classified into subtypes and lineages. Current flu vaccines in the U.S. guard against two subtypes of influenza A viruses, called H1N1 and H3N2, and one influenza B virus lineage, known as the Victoria lineage. (Until very recently, the shots also guarded against a second lineage, called "Yamagata," but it's likely extinct.)

The flu component of the new vaccine contains genetic instructions for human cells to make glycoproteins — molecules of protein and carbohydrate — found in these four flavors of influenza A and B viruses. These glycoproteins, known as hemagglutinins (HA), are located on the surface of flu viruses and enable the viruses to latch onto host cells and initiate infection. Once made, these proteins are shown to the immune system so it can recognize the viruses and fight them off.

Likewise, the COVID component of the new vaccine contains the genetic instructions to make the proteins displayed by SARS-CoV-2, called spike proteins.

"mRNA vaccine is the vaccine of the future, particularly when you want to respond to rapidly changing diseases or new variants," Chin-Hong said. Whereas the molecules in mRNA vaccines can be manufactured very quickly as a virus evolves, conventional flu vaccines take months to make. Chin-Hong described mRNA vaccine production as "cutting and pasting a code"; the mRNA that encodes the virus protein can be conveniently incorporated into the platform.

Moderna has already completed Phase 3 clinical trials for the individual flu and COVID components of its new combo vaccine.

On its own, the flu shot triggered higher immune responses than two conventional flu vaccines — Fluarix and the high-dose Fluzone — against A(H1N1) and A(H3N2) strains. It triggered comparable immune responses against influenza B viruses, based on the trial results. Moderna also showed that its new COVID vaccine induced greater immune responses than Spikevax — the FDA-approved shot — against XBB.1.5, a version of the omicron variant that's been circulating recently. Both vaccines were tested on adults ages 18 and older.

How did the combination vaccine perform?

The purpose of Moderna's latest Phase 3 clinical trial was to measure the robustness of the immune response the mRNA-1083 vaccine triggers in people. The trial runners measured this by looking at the number of antibodies vaccinated people produced against both the flu and the SARS-CoV-2 viruses. Real-world data, which would indicate whether the vaccine effectively lowers rates of hospitalization or emergency visits from the infections, is not yet available.

Consistent with these earlier studies on individual vaccines, the mRNA-1083 combination shot triggered a strong immune response against all four influenza viruses and XBB.1.5.

In the trial, the company recruited two groups of participants: one consisting of adults ages 50 to 64, and another including people 65 and older. Each cohort consisted of about 4,000 adults. The 50-to-64-year-olds received either the new combo shot or a combination of Fluarix and Spikevax. The 65-and-older cohort received either mRNA-1083 or a combination of high-dose Fluzone and Spikevax. (Fluzone, a high-dose flu shot, is approved for adults ages 65 and older and some younger people with weakened immune systems.)

The researchers sampled the trial participants' blood at Day 1 and Day 29 of the experiment to measure the levels of antibodies. They found that the mRNA-1083 vaccine triggered a more robust immune response — as reflected in higher levels of antibodies — than the other vaccine combinations against the SARS-CoV-2 variant.

It also triggered a stronger antibody response against all four influenza strains compared with Fluarix, and three influenza subtypes — H1N1, H3N2 and Victoria — compared with Fluzone.

Will the combo vaccine be tested in younger adults?

While the individual components of the new vaccine have been tested in individuals ages 18 to 49, the latest clinical trial for mRNA-1083 did not include this population.

"It was done in people who are at the highest risk of getting in trouble medically [from both the flu and COVID-19]," said Dr. Robert Schooley, an infectious-disease specialist at the University of California, San Diego. "But it doesn't mean that if you're under 50, you don't want to get a booster shot." Everyone 6 months and older is recommended to get an updated COVID-19 shot when new ones become available, typically on an annual basis.

In a recent statement, Moderna announced that the company is deprioritizing further research on mRNA-1083 testing in adults ages 18 to 49. In the same announcement, the company cited an effort to reduce its operational expenses as a factor in the decision. It is unclear if or when the company might resume testing in this age group.

Does the combo shot have more side effects?

Based on the clinical trial results, the likelihood of mild side effects — such as fever, fatigue and chills — was higher with the combination vaccine than with the currently available vaccines given separately.

"These are expected. The side effect is actually your immune system waking up, and likely shows that you'll get a very durable response," Chin-Hong said.

He also added that serious side effects are very uncommon for both the already-approved COVID and flu shots and in the trials of the new combo vaccine. There were no serious side effects related to the new vaccine, the trial runners reported.

When could the vaccine be approved?

Moderna initially applied for FDA approval back in 2024, using the preliminary results from the same Phase 3 trial. At the time, the FDA asked for more data to show efficacy against the flu. With more data in hand, the company is now "targeting approval" for the vaccine in 2026, according to a recent statement.

However, when it comes to mRNA vaccines, both scientific and political factors are at play, Chin-Hong said.

"The science is unmistakable: it [mRNA] is very nimble; it is durable; it is effective in general," he said. But he pointed out that mRNA vaccine technology itself has been the target of political criticism in the U.S. that traces back to the COVID-19 pandemic, when the vaccines' development was expedited and safety concerns were raised. Even though mRNA vaccines have proved to be very safe and effective, this history may pose a barrier to FDA approval of the new combination vaccine, Chin-Hong said.

In addition, the existence of already-approved separate vaccines for flu and COVID-19 may lessen the urgency in getting the mRNA-1083 approved, he added.

Research funding through the National Institutes of Health (NIH) has been widely cut or frozen, and research on vaccine hesitancy and the boosting of vaccination rates was specifically affected. Experts told NPR that they're concerned mRNA research will soon face similar cuts. NIH officials were cautioned to keep the term "mRNA" out of grant applications, KFF reported.

There are also uncertainties about whether mRNA-1083 will be subject to the new framework on vaccine approval. On May 1, a Department of Health and Human Services spokesperson told The Washington Post that "all new vaccines will undergo safety testing in placebo-controlled trials prior to licensure." A placebo is an inert or inactive substance, such as a saline shot, that new vaccines would have to be compared against during a clinical trial.

Many trials of brand-new vaccines already include placebos. But when there are already existing and effective vaccines for a given disease, comparing a new shot against a placebo isn't necessarily helpful or ethical. Scientists want to understand how much better the new shot works compared with the previous one.

"I don't think it's ethical to give someone a shot that is a placebo, that can in no way help them, when you know there's an existing technology that can," said Dr. Paul Offit, a virologist, immunologist and director of the Vaccine Education Center at Children's Hospital of Philadelphia.

Because mRNA-1083 is a modified version of an already-approved vaccine, "I'm not sure whether that counts as new," Offit said. He thinks a placebo-controlled trial would not be appropriate in this case.

Although the new combo shot still awaits approval, Gandhi said the current clinical trial results were "already convincing." The Phase 3 clinical trial demonstrated that the vaccine is safe and triggers a robust immune response, she added.

"I don't see any red flags at this point," Schooley said. "I'd be confident to take the vaccine myself."

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

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.

Measles kills between 1 and 3 out of every 1,000 children infected with the viral disease. But even for those who survive the illness, the long-term consequences of measles can be serious. Long after a person recovers from their acute infection, their immune system is compromised — and in rare cases, the measles virus can hide out in the nervous system, roaring back to cause a fatal disease years later.

In the short term, measles, caused by a highly contagious virus, usually causes fever, respiratory symptoms like coughing, and a distinctive rash that spreads from the hairline down the body. It appears as if a "bucket of rash" is poured over the head, according to Patsy Stinchfield, an infectious disease nurse practitioner and the most recent past president of the non-profit National Foundation for Infectious Diseases (NFID).

Because the two-shot measles, mumps, and rubella (MMR) vaccine is 97% effective at preventing measles, many U.S.-based medical professionals have never seen the disease that's now causing a major outbreak in Texas and bordering states, experts told Live Science. Cases have been so low in the U.S. that measles was declared eliminated from the country in 2000.

However, Stinchfield responded to a 2017 measles outbreak in Minnesota and saw multiple kids affected.

"The kids that come into the emergency room and get to go home, even those kids look like rag dolls over their parents' shoulders," Stinchfield told Live Science. "They're miserable."

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

An estimated 1 out of every 5 kids who catch measles will be hospitalized, and 1 in 20 will get pneumonia, which is what kills most children who die of the disease, according to the Centers for Disease Control and Prevention (CDC). Some of these hospitalized children will need to be put on a ventilator to recover, Stinchfield said.

In about 1 in 1,000 cases, measles causes brain swelling, or encephalitis, which can cause seizures. When it's not fatal, the swelling itself can subside, but it can cause permanent brain damage and other lasting side effects, such as blindness or deafness.

"Immune amnesia"

Even patients with milder cases of measles can suffer long-term knock-on effects.

Measles binds to a receptor that happens to be present on several important immune cells: T lymphocytes, B lymphocytes, and long-lived plasma cells. These are cells that "remember" past infections for decades, thus enabling the immune system to rapidly mount a defense if it encounters a pathogen again.

It does this by making protective proteins called antibodies, along with summoning other immune defenders. But a 2019 study found that, after a measles infection, people lose between 11% and 73% of the antibodies they had to previous infections.

To recover from this so-called immune amnesia, a person would have to catch all those diseases again, said Stephen Elledge, a geneticist at Harvard Medical School and the senior author of that 2019 research. In the meantime, that means they're vulnerable to a whole host of infections after contracting measles.

Furthermore, a 2015 study led by Elledge's collaborator, epidemiologist Dr. Michael Mina, found that kids who got measles had a higher death rate from other infectious diseases in subsequent years.

These infectious diseases, including measles, are the primary reason that nearly 1 in 5 children died before their fifth birthday in the U.S. back in 1900. A 2024 study published in The Lancet estimated that vaccination has saved at least 154 million lives since 1974, alone.

"The vaccine is much more important than we thought it was," Elledge told Live Science. "It doesn't just save from the 0.1% or 0.2% of children that die [of measles]. It may be the 0.5% to 1% of the kids that get measles [and] might succumb to another infection. That starts to get a little bit bigger."

A lingering threat

The measles virus is capable of replicating in the brain, said Ross Kedl, a professor of immunology at the University of Colorado Anschutz Medical Campus. In some cases, the immune system beats the virus back and the person seems to recover, but measles still lurks in their nervous system.

The nightmarish effect of this long-term persistence is a condition called subacute sclerosing panencephalitis (SSPE). This is a progressive neurological disorder that might start with mood changes and muscle tremors; then, as it progresses, the person starts losing speech, vision and hearing. After about two years, the person falls into a coma and dies.

"The person you knew transforms in front of you and wastes away and then they're gone," Kedl told Live Science.

The risk of SSPE is highest in kids who catch measles before the age of 2, at about 1 in 1,000, Kedl said. For older patients, the risk is closer to 1 in 10,000, which is still twenty times higher than the risk of serious side effects from any vaccine on the market, he said. (1 in 10,000 is 20 in a million, whereas serious adverse events from vaccines occur at a rate of roughly 1 to 2 per million, according to the Department of Health and Human Services.)

Because SSPE is most common in kids who catch measles before age 2, and it tends to emerge about seven years after their acute infection, the victims are typically around the age of 9 or 10.

SSPE happens because the measles virus can go dormant within the nervous system, similar to how the chickenpox virus — called varicella — can go dormant and cause shingles decades later. One benefit of the varicella vaccine is helping prevent the chickenpox infections that can lead to shingles down the line; similarly, the MMR vaccine prevents SSPE.

Measles vaccines save lives and prevent disability

The MMR vaccination has effectively cratered the annual number of U.S. measles cases — which totalled 3 million to 4 million before vaccines were introduced, according to the CDC. Because of the vaccine's success, people forget how bad the disease can be, said Dr. Michelle Barron, senior medical director of infection prevention and control at UCHealth, a medical system in Colorado.

With vaccination rates sliding in various jurisdictions, there are now active measles outbreaks in Texas, New Mexico, Kansas and Ohio, with scattered cases in 16 other states, Barron told Live Science. There are also outbreaks in Mexico and Canada. It's important to be vaccinated to protect both yourself and those who can't be vaccinated, including babies under 1 year old, she said.

There are no treatments for measles that can reduce the risk of the disease's knock-on complications, Barron said. The "natural" remedies that have been pushed by Robert F. Kennedy, Jr. and others, such as vitamin A, are not measles treatments. Rather, they are treatments for malnutrition that are often used to help support kids with measles in places with extreme poverty and childhood malnourishment, Barron said.

What does cut the risk of knock-on effects of measles? Not catching the disease in the first place.

"Vaccine is protective against all of these complications," Barron said.

Editor's note: This article was originally published on April 3, 2025.

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

In the United States, an estimated 645,000 men ages 20 to 50 have azoospermia, a condition in which no sperm are present in their ejaculate. Now, scientists are testing a potential treatment: transplanting sperm-forming stem cells into the reproductive system.

"If refined and proven safe, spermatogonial stem cell (SSC) transplantation could be a revolutionary fertility-restoring technique for men who've lost the ability to produce sperm," Dr. Justin Houman, an assistant professor of urology at Cedars-Sinai Medical Center who was not involved in the study, told Live Science in an email.

It could be especially helpful for "cancer survivors treated before puberty or men with genetic or acquired testicular failure," he added.

So what does this experimental treatment involve?

Related: Sperm cells carry traces of childhood stress, epigenetic study finds

Sperm-forming stem cells are at the core of the therapy. These cells, found in the testicles even before puberty, typically mature into sperm when testosterone levels rise during adolescence.

But medical conditions — like a blockage in the reproductive tract or certain genetic mutations or hormonal problems — and treatments such as chemotherapy can damage these stem cells or block their development into sperm, thus leading to infertility.

If a young patient wishes to preserve their sperm-forming stem cells for future use, doctors can use an ultrasound-guided needle to collect the stem cells into the rete testis — a network of small tubes that connects to the seminiferous tubules, where sperm are typically produced. The needle is carefully inserted into these tubes through the base of the scrotum, and once collected, the stem cells are frozen.

Later on, doctors can then reintroduce the preserved stem cells into the rete testis, using a similar, ultrasound-guided technique. The goal is for the cells to implant in the seminiferous tubules, where they can mature and begin producing sperm, mimicking the natural process that occurs during puberty.

This procedure has previously been tested in animals, and it successfully enabled male mice and monkeys to produce sperm and father offspring.

Now, researchers have documented the technique's first use in humans. According to a paper published March 26 on preprint server medRxiv, a man in his early 20s has now received a transplant of his own, once-frozen stem cells. He had his sperm-forming stem cells preserved as a child, before he underwent chemotherapy for bone cancer.

If the stem-cell transplant is successful, the man's body should begin producing sperm, which was not possible before the procedure due to azoospermia. So far, ultrasounds have confirmed that the transplantation procedure didn't damage the patient's testicular tissue, and his hormone levels are normal.

No sperm have been detected in his semen yet, but the researchers are continuing to analyze his semen twice a year to see if the reproductive cells show up.

One possible reason for the lack of detectable sperm, according to the researchers, is that only a small quantity of stem cells were collected in the patient's childhood, to minimize harm to his tissues. That means the number of preserved and transplanted cells capable of developing into sperm remains low. As a result, sperm production may be limited.

Related: 100 million-year-old sperm is the oldest ever found. And it's giant.

If sperm do not ever appear in the patient's ejaculate but the patient wants to father children, doctors could attempt to recover, via surgery, any small amount of sperm made by the stem cells.

Dr. Laura Gemmell, a reproductive and endocrinology fellow at the Columbia University Fertility Center, suggested another alternative: a technique called the Sperm Tracking and Recovery (STAR) System. This is a machine developed at the Columbia University Fertility Center that combines artificial intelligence technology, robotics, and microfluidics, a technology that uses tiny channels to analyze fluid within a device. This tech identifies and recovers extremely scarce sperm cells from an ejaculate, she told Live Science in an email.

It takes only one sperm to conceive a child, Gemmel noted. "If we can find that sperm noninvasively, we can inject that single sperm into an egg and make an embryo," Gemmel said.

She added that, "our field has seen success with ovarian cryopreservation and retransplantation in young girls with childhood cancers. I'm hopeful that in the future, we can provide an option for young boys who want to one day father a biologic child."

As with all medical procedures, sperm stem cell transplants come with some risks.

For example, there's a chance that a fraction of the transplanted stem cells have cancer-causing genetic mutations and could someday develop into a tumor, especially in patients who've had leukemia in the past, Houman said. And even though the procedure uses the patient's own cells, there's a "theoretical risk" that the immune system could still react and trigger inflammation, he said.

There are also ethical concerns around freezing the sperm stem cells from young boys — namely, how can doctors be sure the children can fully consent to the procedure, and that they have clear expectations around the long-term storage of their cells?

"We need to proceed cautiously, and with rigorous oversight," he said. "This is promising science — but it's still early days."

Editor's note: This story was updated on April 7, 2025, to correct the spelling of Dr. Laura Gemmell's name.

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

Hundreds of people have caught measles in the United States this year, with the majority of the cases tied to outbreaks of the disease. So far, Texas has been the hardest hit, with the highest number of reported illnesses.

According to data from the Centers for Disease Control and Prevention (CDC), 301 people in the U.S. have had confirmed measles infections this year, as of March 13. Additional, probable cases have been reported by various states, but they've yet to be independently confirmed by the CDC.

Kids under 5 years old account for 34% of the confirmed measles cases, with a further 42% affecting children and teens ages 5 to 19. In total, 17% of the cases have resulted in hospitalization.

There has been one confirmed death related to the outbreaks, and a second remains under investigation. The first fatal case was in an unvaccinated school-age child in Texas, marking the first death from measles in the U.S. since 2015. The second deadly case was reported in a New Mexico resident by local health authorities, but the CDC has yet to conclude its own investigation of the case, which would help confirm its connection to ongoing outbreaks.

Related: US measles outbreak tops 300 cases — what to know about the disease

The vast majority of the confirmed measles infections — 95% — have been in people who were unvaccinated or had unknown vaccination status. Additionally, most of the infections have been reported in Texas, with data from the Texas Department of State Health Services showing that 279 measles cases were identified between late January and March 18.

Experts say the Texas outbreak is likely related to low rates of vaccination in the state. For instance, data suggest that around 18% of school-age children in Gaines County have been exempted from at least one vaccine, and 191 measles cases have occurred in that county so far. Meanwhile, Gaines' neighboring counties of Dawson, Yoakum, Terry and Martin have reported 11, 11, 36 and 3 cases, respectively.

As measles continues to spread, here's what to know about the protection of the measles vaccine, how long it lasts, and how to know if you're immune to the disease.

How effective is the measles vaccine?

Measles can be prevented with the MMR vaccine, which protects against measles, mumps and rubella; or the MMRV vaccine, which additionally protects against the chickenpox-causing varicella virus. The CDC recommends that children receive their first dose of the MMR or MMRV vaccine between the ages of 12 and 15 months and their second dose between 4 and 6 years old.

(For measles protection, the MMR vaccine is generally recommended over the MMRV vaccine, because it's less likely to trigger fevers in children. For those who get the MMR shot, a separate vaccine is recommended to protect against chickenpox (varicella).)

Unvaccinated older children and adults are also advised to receive two doses of a measles vaccine, at least 28 days apart.

One dose of the MMR vaccine is 93% effective at preventing measles, while two doses are 97% effective, according to the CDC. The MMRV vaccine offers the same level of measles protection.

"It's probably one of the best vaccines that we have," Michael Head, a senior research fellow in global health at the University of Southampton in the U.K., told Live Science in an email.

"For example, the COVID-19 vaccines are very good at reducing mortality, but less good at preventing a mild COVID-19 infection," Head said. The measles vaccine is highly protective against measles infections of all severity levels.

Measles was declared eliminated in the U.S. in 2000 thanks to widespread vaccination against the disease. The CDC defines "elimination" as the "absence of continuous disease transmission for 12 months or more in a specific geographic area." Measles is not yet "eradicated" worldwide, meaning it still spreads regularly in other countries and can be imported to the U.S.

How long does the MMR vaccine's protection last?

The MMR vaccine provides long-lasting measles protection for most people, with immunity typically being lifelong after two doses, according to the CDC. However, one 2024 study published in the journal The Lancet Public Health reported that measles immunity does fade slightly over time.

"Like with COVID vaccines, antibody levels do reduce over time," Dr. Peter Chin-Hong, a professor of medicine at the University of California, San Francisco, told Live Science via email. Antibodies are protective immune proteins that appear in the days and weeks after a person receives a vaccine, but these proteins are expected to disappear over time.

"However there is likely continued immunity with memory immune cells that can be activated as needed (as we have seen in COVID vaccines)," Chin-Hong added. When exposed to the measles vaccine, the body generates "memory" cells in the immune system, which can quickly mount an immune response and make new antibodies if a person encounters the measles virus.

"In general, protection once immunized against measles, wanes very little," Chin-Hong said. The Lancet study suggested that, on average, measles immunity waned by about 0.039% per year after the age of 5.

Related: 'A political division, not a physical one, determined who got measles and who didn't': Lessons from Texarkana's 1970 outbreak

Does catching measles give you lifelong immunity?

Yes, if a person survives a bout of measles infection, they typically have lifelong immunity against the virus. However, even as the immune system mounts a powerful response against measles, its guard against other infections gets lowered.

Many studies find that measles infections induce a kind of "immune amnesia," in which memory cells tasked with remembering pathogens are lost and the body is unable to rev up its antibody responses, as it used to. This leaves a person at increased risk of other infections for years following their brush with measles.

Other complications of measles infection include a rare but deadly central nervous system condition called subacute sclerosing panencephalitis (SSPE), which can develop seven to 10 years after the infection. Some people can also experience brain swelling (encephalitis) during a measles infection, which can cause convulsions, permanent hearing loss and intellectual disability.

The measles vaccine provides lifelong immunity against the virus without these dangerous complications associated with measles infection.

Is there a way to check if you're immune to measles?

If you've received two doses of the MMR vaccine, you're considered immune for life in most cases. Additionally, if you've had a confirmed case of measles in the past, you're likely immune for life.

If someone is still unsure whether they've either been vaccinated or had the disease, there's a test that checks for measles-specific antibodies in your blood. The type of measles antibody it screens for belongs to a broad class called immunoglobulin G (IgG), which protects the body from infection by binding to pathogens.

If enough measles-specific IgG antibodies are present, compared to a standard threshold, a person has immunity.

"You can check an antibody level with the help of a health care provider," Chin-Hong said. The test will give you a number back that's called a "titer"; this is a measure of your antibody levels. However, the test will not pick up memory cells, Chin-Hong said, so it could miss that additional layer of evidence that you're immune to measles.

Should anyone get a booster for measles, if they've been fully vaccinated in the past?

If a person is unsure about how protected they are against measles, they can get a booster shot of the vaccine to bolster their immunity.

"It is perfectly safe to have another dose," Head said. "The recommendation to get an extra dose will typically come from public health teams, and it's always best to see the advice of a healthcare worker if anyone is unsure."

If someone has had two doses of the measles vaccine in their lifetime, there is likely no need for a booster shot. The exception is a group of people who received the measles vaccine in the 1960s, who would need an additional MMR vaccine to ensure their protection.

That's because the measles vaccine used in the U.S. between 1963 and 1967 was less effective than modern measles vaccines. Unlike the current shots, which contain live-but-weakened viruses, the old shot contained an inactivated virus, so it was completely "killed." In response to the old vaccine, the immune system did not develop long-lasting memory cells, unlike the vaccines used today. Many people who received the old vaccine lost their immunity within a few years, leaving them vulnerable to measles later in life.

In addition to people who received only this old vaccine, anyone who has gotten only one dose of the MMR or MMRV vaccine is recommended to get the recommended second dose.

The CDC started recommending two doses of the MMR shot in 1989, Chin-Hong noted, so those vaccinated before that time may need a second dose.

Individuals traveling to areas experiencing measles outbreaks, including within the U.S., can also consider getting another dose even if they're fully vaccinated, Chin-Hong said.

Additionally, health care workers, immunocompromised people and those who live with them, and college students should check their vaccination records to confirm they've received two MMR doses, and perhaps get an immunity test if they are unsure, Chin-Hong suggested. Individuals can speak with their health care provider about getting a booster shot, if they're interested in receiving one.

Can vaccinated people still catch measles sometimes?

Fully vaccinated people may still catch measles, but only in rare circumstances.

About 3% of fully vaccinated people may still develop measles symptoms after an exposure to the virus, according to the CDC. However, people who have been fully vaccinated tend to experience milder symptoms than unvaccinated or partially vaccinated individuals, and they are also less likely to spread the virus to others.

These "breakthrough" cases become more likely in the context of large outbreaks or high-exposure settings — when an individual has prolonged, close contact with an infected person. About 5% of total measles cases in the U.S. are breakthrough cases, according to the CDC.

Additionally, people with weakened immune systems — due to medical conditions or medications — might not maintain full protection, even if they're fully vaccinated. So they can be more prone to breakthrough cases.

In the current Texas outbreak, there were a "handful" of people who contracted measles after having only one shot," Chin-Hong noted. In a study that looked at measles cases in California between 2000 and 2015, most of those infected were unvaccinated, but 11% of the total cases were among people who had gotten two doses of measles vaccine. The fully vaccinated group did have milder disease, however.

How high do vaccination rates in a community need to be to reach "herd immunity"?

Herd immunity refers to when a high percentage of a population is immune to a disease, making it difficult for the infection to spread. Reaching this collective level of immunity protects even those who can't be vaccinated, such as newborn babies, pregnant people or immunocompromised people.

Measles is one of the most contagious diseases in the world, and because of that, at least 95% of a given population needs to be immune to prevent major outbreaks.

"Measles is so infectious, with very high levels of transmission. Typically, we refer to 95% coverage as the magic number of that 'herd immunity threshold,'" Head told Live Science. "At this level of coverage, there may still be individual case[s], but the majority of the population is protected, and the outbreaks will remain small and very localised."

MMR coverage among U.S. kindergartners has declined in recent years, according to the CDC. In the 2019-2020 school year, 95.2% of kindergartners had received two doses of the MMR vaccine, but in the 2023-2024 school year, that coverage dropped to 92.7%. That marked the "fourth consecutive year" that national coverage had been below the targeted 95%.

Several states — including Arizona, Utah, Colorado, Oklahoma, Georgia and Florida — had less than 90% coverage during the 2023-2024 school year.

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

More than 600 measles infections have sickened people in the U.S. this year, as of April 4.

That's according to the latest tally of confirmed measles cases from the Centers for Disease Control and Prevention (CDC). Some additional, probable cases have been reported in various places, but the CDC has yet to confirm those infections.

Three fatal cases have occurred this year — one confirmed by the CDC and two that have yet to be officially confirmed. The death of an unvaccinated child in Texas marked the first measles death in the U.S. since 2015. The second death, in a person in New Mexico, still awaits official confirmation. The third death, reported in Texas in April, was in another unvaccinated, school-age child.

The 607 total measles cases across the U.S. have happened in the following states: Alaska, California, Colorado, Florida, Georgia, Kansas, Kentucky, Maryland, Michigan, Minnesota, New Jersey, New Mexico, New York, Ohio, Oklahoma, Pennsylvania, Rhode Island, Tennessee, Texas, Vermont and Washington. Texas has been hardest hit so far, followed by New Mexico and Kansas.

The majority of the CDC-confirmed cases — 567, or 93% — have been related to six measles outbreaks, defined as involving three or more related cases of the disease. About 97% of the cases have impacted people who were unvaccinated or whose vaccination status was unknown.

About 1% of those affected had gotten one dose of the measles vaccine, meaning they were partially vaccinated, while 2% of the cases have occurred in people who were fully vaccinated, having received two doses.

As the case counts tick upward, here's what you need to know about measles, how it spreads and how you can protect yourself and your loved ones against the illness.

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

What is measles, and how does it spread?

Measles is a potentially deadly respiratory infection caused by a virus known as Measles morbillivirus, or simply "the measles virus." The disease exclusively affects humans, meaning it does not infect animals.

Measles is spread from one person to another via droplets in the air, which are released when an infected individual coughs or sneezes, for example.

"[Measles] is probably one of the most contagious viruses that's ever existed," Dr. Ashley Stephens, an assistant professor and pediatrician at Columbia University Irving Medical Center in New York, told Live Science.

Once released into the air from an infected person, droplets containing the measles virus can remain airborne for two hours. Anyone who is nearby who isn't yet immune to the virus then has a 90% chance of also becoming infected if they then breathe in these droplets. The basic reproduction number of measles — an estimate of the average number of susceptible people that an infected individual would pass the illness to — is typically cited as 12 to 18. Estimates for seasonal flu, by comparison, fall between 1 and 2.

What are the symptoms of measles, and how is it treated?

People usually develop symptoms of measles within seven to 14 days of being exposed to the virus. Common initial symptoms of the disease include a high fever, cough and runny nose, as well as red, watery eyes.

After a few days, the characteristic red rash associated with measles appears, typically first on the head before then spreading to the rest of the body. The rash starts out as flat, red spots, and later on, small raised bumps may emerge on top of the spots. The spots can end up joining together as they spread over the body.

Some people additionally get small white spots that appear inside their cheeks and on the backs of their lips, known as Koplik spots.

Measles can go on to cause serious complications, including pneumonia and swelling of the brain, known as encephalitis. These complications are more likely to happen in certain groups, such as children who are under the age of 5, pregnant people and people with weakened immune systems. Approximately 1 to 3 children per 1,000 who are infected with measles die of it, namely from respiratory or neurologic complications.

"Measles is a very dangerous virus, and many people that get infected — particularly children under age 5 — are at high risk of getting really sick from it," Stephens said.

Unfortunately, there is really no good treatment for measles, Stephens added. The disease must run its course, which normally stakes between 10 and 14 days in those who survive. In the meantime, patients may be prescribed drugs to help manage their symptoms, such as acetaminophen for pain relief and to treat fever.

For those who survive a bout of measles, they can still have ongoing health problems afterward. In particular, measles is known to induce a kind of amnesia of the immune system — people end up with immunity against future measles infections, but they become vulnerable to other germs they've encountered in the past. (This "immune amnesia" is most profound in unvaccinated people; the few vaccinated individuals that still catch measles don't suffer these same knock-on impacts.)

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

How common are measles outbreaks in the U.S.?

According to the CDC, 16 outbreaks of measles were reported in the U.S. in 2024, while four were reported in 2023. An outbreak, in this context, means three or more related cases of the disease, the CDC notes.

Before the measles vaccine became available in the U.S. in the 1960s, between three and four million people were infected with the virus every year, and about 500 died. Then, thanks to an effective national vaccination program and improved measles control across North and South America, measles was declared eliminated in the country in 2000. For a disease to be "eliminated," its transmission must be stopped within a specific geographical area; "eradication," by contrast, means a disease has effectively been made extinct worldwide.

Measles is still prevalent elsewhere in the world, so cases can occasionally be imported into the U.S. This can happen when people get infected with measles while traveling overseas and then reenter the country, for example. These imported cases can then spark outbreaks within the U.S.

How can you protect yourself and others against measles?

The best way to avoid getting sick from measles is to be immunized with two doses of the measles vaccine. Most often, people are vaccinated with measles, mumps and rubella (MMR) vaccine, the DSHS said in their statement.

Another option is the MMRV vaccine, which also protects against varicella, the chickpox virus. However, the MMR vaccine is generally recommended over the MMRV because it's less likely to trigger fevers in children.

Children should get their first dose of the MMR vaccine when they are between the ages of 12 and 15 months old, followed by a second dose between 4 and 6 years old. The schedule for the MMRV vaccine is the same.

Teenagers and adults who have received neither dose or only one dose of the MMR vaccine are also eligible to receive it, whereas the MMRV vaccine is only approved for people up to age 12. That said, certain adults shouldn't get a MMR vaccine, including people who are pregnant.

One dose of the MMR vaccine is 93% effective against measles, and that protection rises to 97% following the administration of the second dose. Evidence suggests that people who are fully vaccinated are protected for life against measles, without the need for a booster dose.

Related: 'A political division, not a physical one, determined who got measles and who didn't': Lessons from Texarkana's 1970 outbreak

Why is there controversy around the measles vaccine?

Stephens said that anyone who is concerned about the risk that they or their children get sick from measles should contact their doctor. Their health care provider will also be able to answer any questions concerning the MMR vaccine, she added.

"We understand that many people have found misinformation, so they might have seen something about the MMR vaccine that made them concerned," she said.

One piece of misinformation surrounding the MMR vaccine is that it causes autism — a claim that originated in the late 1990s after a now thoroughly debunked paper was published in the journal The Lancet. The paper purported a link between the vaccine and autism, but its methods were flawed, its data deliberately falsified and its author had a clear conflict of interest. The paper was ultimately retracted.

Despite the overwhelming evidence against it, the link between vaccines and autism is still used by anti-vaccine campaigners to smear the MMR vaccine — a sentiment that has previously been echoed by Robert F. Kennedy Jr, the current United States Secretary of Health and Human Services. Anti-vaccine campaign groups are also presently inaccurately suggesting that the vaccine itself is causing the current outbreak in Texas, NBC News reports.

Editor's note: This story was last updated on April 7, 2025. It will continue to be updated as new information emerges.

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

A strain of bird flu never seen before in the United States has been detected among poultry at a California farm.

The virus, called highly pathogenic H5N9, is a type of avian influenza, otherwise known as "bird flu." This is not the same type of bird flu that's already been spreading on dairy cow and poultry farms in the U.S., causing at least several dozen infections in humans. That virus is called H5N1.

So what is H5N9? How does it differ from H5N1, and should we be equally concerned about it?

Related: Bird flu strikes 1st child in the US — CDC says infection source unknown

What is H5N9?

H5N9 is a highly pathogenic avian flu (or bird flu) virus that bears some structural similarities to H5N1.

"Low pathogenic" H5N9 viruses have previously been detected in birds in the U.S. and elsewhere in the world, dating back to the 1960s. However, these infections are usually associated with less-severe symptoms than "highly pathogenic" strains are. This is the first time highly pathogenic H5N9 has been seen in the U.S., and these deadlier strains are also fairly uncommon worldwide.

How did H5N9 emerge?

New subtypes and strains of influenza can emerge if viruses pick up random genetic mutations as they multiply, as well as if multiple viruses swap genetic information with one another. This latter process is known as genetic reassortment, and it usually happens when an organism is infected with at least two different viruses at the same time.

Some experts suspect that H5N9 may have emerged among the ducks in California due to genetic reassortment occurring between circulating H5N1 viruses and other flu viruses containing the N9 protein. ("H5" and "N9" are two proteins found on the surface of the virus that give the bird flu subtype its name.)

H5N1 was also detected in the birds at the farm, so this could be plausible, according to a Jan. 24 report from the World Organisation for Animal Health (WOAH), which monitors disease outbreaks in animals worldwide.

Such reassortment can lead to "unpredictable new viruses," Angela Rasmussen, a virologist at the University of Saskatchewan in Canada, wrote on X.

She added that ducks may be great host animals for genetic reassortment to take place because, unlike chickens, they don't get very sick from many avian flu viruses. Therefore, while an infected chicken would quickly die, ducks can survive and continue to spread the disease to new hosts.

Related: How to avoid bird flu

What's happening at the farm where H5N9 was detected?

In the Jan. 24 report, the WOAH announced that H5N9 had been identified at a duck farm in Merced County, California. The current outbreak, which the report says was confirmed on Jan. 13, is being closely monitored by officials.

"The USDA Animal and Plant Health Inspection Service (APHIS), in conjunction with State Animal Health and Wildlife Officials, are conducting comprehensive epidemiological investigations and enhanced surveillance in response to the HPAI [highly pathogenic avian influenza] related events," the WOAH wrote in the report.

To prevent further spread of the infection, all of the nearly 119,000 birds at the farm have now been culled. These bird flu viruses are known as "highly pathogenic" because they are extremely deadly to certain poultry — like chickens — and culling an exposed flock is typically considered the best way of preventing additional flocks from getting sick.

Why is bird flu concerning?

Scientists have recently expressed increasing concern that a strain of bird flu could mutate into a form that easily spreads among humans, sparking a pandemic. This happened during historic pandemics, such as the "Spanish flu" in 1918 and the "Asian flu" in 1957.

Humans can become infected with avian influenza if the virus gets into their eyes, nose or mouth, or if it is inhaled in the form of droplets in the air. However, not all bird flu viruses are equipped to efficiently infect people and then spread between them. When given more chances to spread to new animals, the viruses have a higher chance of picking up that ability and harming humans.

Notably, over the past couple of years, H5N1 has spread to new countries, including the U.S. It's been widely infecting wild birds and poultry and has also jumped into various mammals, including cattle and domestic cats. Since its discovery, H5N1 has infected more than 900 people globally, and in the past year, at least 67 people in the U.S. have been infected. In December 2024, a woman in Louisiana became the first person in the U.S. to die as a result of an H5N1 infection.

Related: Bird flu could become deadlier if it mixes with seasonal flu viruses, experts warn

How does H5N9 differ from H5N1?

Avian influenza viruses come in different subtypes, which are named according to subtle variations in the structure of two key proteins on the surface of the virus: hemagglutinin (H) and neuraminidase (N). So H5N9 and H5N1 have the same hemagglutinin protein, but a different neuraminidase protein.

A virus's specific combination of H and N proteins determines a range of important traits, such as how good it is at spreading from one animal to another, how deadly it is, and whether it is resistant to antiviral treatment.

Besides the difference in their neuraminidase proteins, H5N9 differs from H5N1 in several other ways.

For example, H5N1 infections are more common among humans and are believed to be the deadliest of all the highly pathogenic avian influenza strains in humans and chickens.

Does H5N9 pose a risk to humans?

As of yet, little is known about whether H5N9 could spread to humans and potentially cause a pandemic.

On its website, the Centers for Disease Control and Prevention (CDC) currently states that the public health risk from H5 bird flu is "low" but that the agency is "watching the situation carefully and working with states to monitor people with animal exposures." The CDC's primary focus on that webpage is H5N1, but the agency is monitoring H5 viruses broadly, using its flu surveillance systems to watch for any cases in humans.

As of Jan. 18, there has been no evidence of H5 bird flu spreading from one human to another in the U.S.

"The combination H5N9 is not new and other versions, like H5N5 also exist," Florian Krammer, a professor of vaccinology at the Icahn School of Medicine at Mount Sinai in New York, told CBS News. "Just because this was now detected, doesn't mean trouble necessarily," he emphasized.

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

Less than two weeks ago, a scarcely known Chinese company released its latest artificial intelligence (AI) model and sent shockwaves around the world.

DeepSeek claimed in a technical paper uploaded to GitHub that its open-weight R1 model achieved comparable or better results than AI models made by some of the leading Silicon Valley giants — namely OpenAI's ChatGPT, Meta’s Llama and Anthropic's Claude. And most staggeringly, the model achieved these results while being trained and run at a fraction of the cost.

The market response to the news on Monday was sharp and brutal: As DeepSeek rose to become the most downloaded free app in Apple's App Store, $1 trillion was wiped from the valuations of leading U.S. tech companies.

And Nvidia, a company that makes high-end H100 graphics chips presumed essential for AI training, lost $589 billion in valuation in the biggest one-day market loss in U.S. history. DeepSeek, after all, said it trained its AI model without them — though it did use less-powerful Nvidia chips. U.S. tech companies responded with panic and ire, with OpenAI representatives even suggesting that DeepSeek plagiarized parts of its models.

Related: AI can now replicate itself — a milestone that has experts terrified

AI experts say that DeepSeek's emergence has upended a key dogma underpinning the industry's approach to growth — showing that bigger isn't always better.

"The fact that DeepSeek could be built for less money, less computation and less time and can be run locally on less expensive machines, argues that as everyone was racing towards bigger and bigger, we missed the opportunity to build smarter and smaller," Kristian Hammond, a professor of computer science at Northwestern University, told Live Science in an email.

But what makes DeepSeek's V3 and R1 models so disruptive? The key, scientists say, is efficiency.

What makes DeepSeek's models tick?

"In some ways, DeepSeek's advances are more evolutionary than revolutionary," Ambuj Tewari, a professor of statistics and computer science at the University of Michigan, told Live Science. "They are still operating under the dominant paradigm of very large models (100s of billions of parameters) on very large datasets (trillions of tokens) with very large budgets."

If we take DeepSeek's claims at face value, Tewari said, the main innovation to the company's approach is how it wields its large and powerful models to run just as well as other systems while using fewer resources.

Key to this is a "mixture-of-experts" system that splits DeepSeek's models into submodels each specializing in a specific task or data type. This is accompanied by a load-bearing system that, instead of applying an overall penalty to slow an overburdened system like other models do, dynamically shifts tasks from overworked to underworked submodels.

"[This] means that even though the V3 model has 671 billion parameters, only 37 billion are actually activated for any given token," Tewari said. A token refers to a processing unit in a large language model (LLM), equivalent to a chunk of text.

Furthering this load balancing is a technique known as "inference-time compute scaling," a dial within DeepSeek's models that ramps allocated computing up or down to match the complexity of an assigned task.

This efficiency extends to the training of DeepSeek's models, which experts cite as an unintended consequence of U.S. export restrictions. China's access to Nvidia's state-of-the-art H100 chips is limited, so DeepSeek claims it instead built its models using H800 chips, which have a reduced chip-to-chip data transfer rate. Nvidia designed this "weaker" chip in 2023 specifically to circumvent the export controls.

A more efficient type of large language model

The need to use these less-powerful chips forced DeepSeek to make another significant breakthrough: its mixed precision framework. Instead of representing all of its model's weights (the numbers that set the strength of the connection between an AI model's artificial neurons) using 32-bit floating point numbers (FP32), it trained a parts of its model with less-precise 8-bit numbers (FP8), switching only to 32 bits for harder calculations where accuracy matters.

"This allows for faster training with fewer computational resources," Thomas Cao, a professor of technology policy at Tufts University, told Live Science. "DeepSeek has also refined nearly every step of its training pipeline — data loading, parallelization strategies, and memory optimization — so that it achieves very high efficiency in practice."

Similarly, while it is common to train AI models using human-provided labels to score the accuracy of answers and reasoning, R1's reasoning is unsupervised. It uses only the correctness of final answers in tasks like math and coding for its reward signal, which frees up training resources to be used elsewhere.

All of this adds up to a startlingly efficient pair of models. While the training costs of DeepSeek's competitors run into the tens of millions to hundreds of millions of dollars and often take several months, DeepSeek representatives say the company trained V3 in two months for just $5.58 million. DeepSeek V3's running costs are similarly low — 21 times cheaper to run than Anthropic's Claude 3.5 Sonnet.

Cao is careful to note that DeepSeek's research and development, which includes its hardware and a huge number of trial-and-error experiments, means it almost certainly spent much more than this $5.58 million figure. Nonetheless, it's still a significant enough drop in cost to have caught its competitors flat-footed.

Overall, AI experts say that DeepSeek's popularity is likely a net positive for the industry, bringing exorbitant resource costs down and lowering the barrier to entry for researchers and firms. It could also create space for more chipmakers than Nvidia to enter the race. Yet it also comes with its own dangers.

"As cheaper, more efficient methods for developing cutting-edge AI models become publicly available, they can allow more researchers worldwide to pursue cutting-edge LLM development, potentially speeding up scientific progress and application creation," Cao said. "At the same time, this lower barrier to entry raises new regulatory challenges — beyond just the U.S.-China rivalry — about the misuse or potentially destabilizing effects of advanced AI by state and non-state actors."

For the first time, the U.S. Food and Drug Administration (FDA) has approved the use of a ketamine-like drug as a stand-alone therapy for adults with treatment-resistant depression (TRD). The drug is approved only for use in a clinical setting under the supervision of a health care provider.

TRD is a severe type of major depressive disorder in which patients' symptoms are not relieved by standard antidepressants — specifically, patients with TRD have not responded to at least two courses of antidepressant treatments in the past. The condition is believed to affect around one-third of adults with major depressive disorder, so there is a considerable need for new, effective treatments for TRD.

Esketamine, a molecular relative of regular ketamine, was approved as a TRD treatment in 2019, but until now, it had to be taken alongside a second, traditional antidepressant. Now, the new FDA approval means that patients will be able use the ketamine-derived nasal spray, which is marketed under the brand name Spravato, without having to be on another type of antidepressant, according to a statement from the drug's manufacturer, Janssen Pharmaceuticals, that was published online Jan. 21.

But what is esketamine? And what will the new FDA approval mean in practice?

Related: How does ketamine work as an antidepressant? It's complicated.

What is esketamine?

Esketamine is like a "sibling" of the anesthetic ketamine in that it's made from the same building blocks as the latter drug but it's arranged in a subtly different way. Ketamine contains molecules with two distinct molecular "orientations," meaning their atoms are aligned in a particular way. Esketamine, on the other hand, contains molecules with just one of these two orientations.

This chemical difference means esketamine can be inhaled through the nose, while ketamine must be injected. Esketamine is also more potent, so it can be used at lower doses. (Ketamine, although most often used as an anesthetic, can be provided off-label for depression.)

How does esketamine treat depression?

It's unclear exactly how esketamine exerts its antidepressant effects, but the drug is thought to influence the transmission of a chemical messenger called glutamate in the brain, which plays important roles in mood regulation. Traditional antidepressants generally target other chemicals in the brain, such as serotonin and norepinephrine. Esketamine also works differently than so-called classic psychedelics, like psilocybin and LSD, which affect serotonin signaling.

Off the back of clinical trials of the drug, the FDA approved esketamine under the brand name Spravato in 2019. It was initially cleared as an "add-on" treatment for patients with TRD who were already taking another oral antidepressant.

So far, more than 80,000 people in the U.S. have already been treated with Spravato, according to the manufacturer's website. And now, as a result of the latest FDA approval, Spravato can also be taken as a stand-alone treatment, potentially opening the door for more people to use it.

What has led to the new FDA approval?

The new FDA approval came after a clinical trial found that 22.5% of patients who took Spravato alone for four weeks entered remission — in other words, they effectively no longer had depressive symptoms — compared with 7.6% of patients who took a placebo instead. There were also "no new safety concerns" associated with taking the drug in isolation, compared with taking it with another antidepressant.

Who could benefit from the new approval of esketamine?

"Esketamine has been a transformative treatment for depression symptoms that have not responded to other treatments," Dr. John Krystal, a professor of neuroscience at Yale University, told Live Science in an email.

The new FDA approval will target two main groups, Krystal said. First, it could help patients who previously didn't respond to two antidepressant treatments and who are not currently being treated with one.

"Some of these people may have episodes of antidepressant medication spaced by several years," Krystal said, and they wouldn't have been able to use esketamine during those gaps. "Their poor experiences with prior treatments may have been an obstacle to seeking needed help for their depression." Because of the new approval, these patients will now be able to start esketamine treatment without having to also begin taking another type of antidepressant, Krystal clarified.

A second group of people that could benefit includes patients who have tried at least two antidepressants but who wish to stop taking their current treatment when they start esketamine.

"The most common reason that they [these patients] would want to discontinue the ineffective antidepressant is side effects," Krystal said. "Antidepressants may have side effects, including headache, weight gain, sedation, and sexual side effects — the new FDA ruling makes it possible for these people to be treated with esketamine without needing to continue their prior antidepressant."

Does esketamine have any side effects?

Taking esketamine is not completely without risk. In fact, the FDA has approved its use through a restricted program known as the Spravato Risk Evaluation and Mitigation Strategy (REMS) program, which allows patients to take the drug only under the supervision of a health care provider in a clinic and not on their own at home.

That's because patients may experience sedative and dissociative effects while taking Spravato. Dissociation is when people feel detached from their body or physical surroundings which can include issues with perception. In clinical trials, 41% of patients who took Spravato combined with an oral antidepressant experienced dissociation.

Ketamine and its derivatives also come with a risk of addiction, so there are concerns that unsupervised patients could misuse or abuse esketamine.

Through the REMS program, patients using Spravato also must be monitored for at least two hours after treatment. Treatments are recommended to occur twice a week for the first four weeks and then once a week for the following three weeks. They can be scheduled once a week or every other week thereafter.

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

For the first time, the U.S. Food and Drug Administration (FDA) has authorized the marketing of nicotine pouches, synthetic packs of nicotine designed to be placed under a person's lip.

In a statement published Jan. 16, the agency stated that 20 different Zyn nicotine pouch products can now be marketed to adults ages 21 and over. That doesn't mean the pouches are now "FDA approved" as drugs intended to treat disease would be, nor that they are safe. Rather, the pouches have met the FDA's criteria for nicotine-based products that can be sold to the public.

After an "extensive scientific review," the FDA said the pouches have met the public health standard set by the 2009 Family Smoking Prevention and Tobacco Control Act, which weighs the overall risks and benefits that such products would pose to the general population. The agency notes that the pouches contain lower levels of harmful substances than cigarettes do and thus pose a lower risk of cancer and other serious health issues.

However, some public health and medical organizations claim that by authorizing the marketing of these products, the FDA has ignored their warnings about how dangerous the products could be to young people. Meanwhile, other experts have cautioned that there is not yet enough scientific evidence to support their use as a smoking cessation tool. The FDA's statement suggests that the pouches could be helpful in the event that people who smoke completely switch to the pouches instead.

Here's everything we know so far about nicotine pouches and the new FDA authorization.

Related: Simple vaping 'quitline' can help over 40% of young people quit, study finds

What does the FDA authorization mean?

The new FDA authorization means that 10 flavors of Zyn nicotine pouches can now be legally marketed in the U.S. to adults ages 21 and over. These 10 flavors come in two nicotine doses: 3 and 6 milligrams. The company markets these flavors as chill, cinnamon, citrus, coffee, cool mint, menthol, peppermint, smooth, spearmint and wintergreen.

In its Jan. 16 statement, the FDA notes that this latest authorization does not mean that these products are safe for use or that they are "approved" by the agency. This is as opposed to several types of nicotine-replacement therapies, including "nicotine gum" and "nicotine patches," which have been approved by the FDA as quit-smoking aids. These latter products have been shown are much less addictive than cigarettes, don't cause death or disease and are usually only used temporarily.

Products like Zyn don't need to be proven safe and effective for a specific population — the manufacturer just needs to comply with "requirements under the law to bring its product to market," the FDA website says. In addition, the FDA assesses whether a given product would offer more benefits than risks to the general population, considering the population as a whole, including users and nonusers of tobacco products. It weighs, for example, whether people who currently smoke might benefit from switching to the new product, or if nonusers might be likely to start using nicotine for the first time once the new product hits the market.

What are nicotine pouches?

Nicotine pouches like Zyn are small, rectangular bags of powder that are placed between a person's lip and gums to deliver nicotine. They don't contain any of the tobacco found in conventional smoking products, such as cigarettes and cigars. Nicotine from the pouches enters the bloodstream and makes its way to the brain via the oral mucosa — the wet, soft tissues that line the mouth.

"Nicotine pouches are a relatively new category of tobacco products that are unique because they contain a crystallized nicotine powder instead of tobacco leaf," Tory Spindle, an associate professor of psychiatry and behavioral sciences at Johns Hopkins Medicine, told Live Science in an email.

"This means that they generally contain fewer harmful ingredients compared to traditional tobacco products," he said. Products like cigarettes contain both tobacco and a variety of additives, both of which contain carcinogens.

But nicotine pouches aren't free of harmful chemicals. "They do still contain nicotine which is an addictive substance as well as other substances such as flavorants," Spindle said. A study published in the journal Tobacco Control in 2022 found that 26 of 44 sampled nicotine pouch products contained cancer-causing chemicals known as tobacco-specific nitrosamines. The nicotine in the pouches can be derived from tobacco plant extracts, explaining how these chemicals end up in the products.

The same study also found that each of the sampled pouches contained between 1.79 and 47.5 mg of nicotine. By comparison, cigarettes contain an estimated 6.17 to 12.65 mg and e-cigarettes release about 0.5 to 15.4 mg per 300 puffs, while nicotine patches or gum release up to 21 mg or 4 mg of nicotine. So, depending on the brand, nicotine pouches still deliver substantial amounts of nicotine compared with other products on the market.

Can nicotine pouches help people quit smoking?

For a product to receive marketing authorization, there needs to be sufficient evidence that it offers greater benefits than risks to the health of the general population, Matthew Farrelly, director of the Office of Science in the FDA's Center for Tobacco Products, said in the agency's Jan. 16 statement.

"In this case, the data show that these nicotine pouch products meet that bar by benefiting adults who use cigarettes and/or smokeless tobacco products and completely switch to these products," Farrelly said.

However, experts are unconvinced that there is enough scientific evidence to support the idea that adult smokers will actually make the switch.

Related: Nicotine vapes are one of the best tools to help people quit smoking, review of 300 trials suggests

"There are some anecdotal reports of people switching from smoking or using traditional oral tobacco products such as 'dip' or 'chew' to nicotine pouches," Spindle said. "But the gold standard research studies needed to answer this question (randomized controlled trials) have not been done."

Randomized controlled trials allow scientists to directly assess whether one factor causes another. In this case, such a trial would likely involve a large group of people who currently smoke, a percentage of whom would be given nicotine pouches to see whether they're more likely to quit than people given a different intervention or nothing at all.

One recent scientific review, published in 2024 in the journal Experimental and Clinical Psychopharmacology, suggested that oral nicotine pouches may be a "viable harm reduction" option for people who switch over completely from conventional tobacco products. However, that review also concluded that randomized controlled trials are needed to determine if people will continue to use the pouches in the long term. More independent research on the topic, not funded by the tobacco industry, is also needed, the review states.

What are the potential risks of using nicotine pouches?

Nicotine pouch use is associated with several health effects, including addiction to the nicotine within them, Spindle said. These effects can be particularly pronounced for younger people, who may still use the products despite the new authorization only allowing marketing towards over-21s.

"Developing an addiction to a substance can have negative impacts on the developing brain, which is why it is important for kids not to use them," Spindle said. Exposure to nicotine during adolescence can alter signaling between neurons in the prefrontal cortex of the brain. This part of the brain controls an array of cognitive functions, including decision-making and reasoning, and it's one of the last regions of the brain to mature.

Nicotine pouches are also known to cause side effects, such as nausea and mouth sores. Because they don't include all of the harmful substances found in traditional tobacco products, some people might assume that the pouches have fewer long-term health effects. However, that's not known for sure, and their impact on oral health is particularly unclear, Spindle said.

The FDA says it will "closely monitor the marketing and use of these products," according to the Jan. 16 statement. This monitoring will include ensuring that the marketing of the patches online, on TV and on the radio is targeted to adults ages 21 and over.

But several organizations have raised concerns about whether this level of regulation will be enough to curb the use of nicotine pouches by younger groups. The flavors of authorized Zyn products are likely to appeal to this demographic, the organizations noted.

"While it has not been sold in the U.S. for long, we are already seeing very concerning levels of youth use [of Zyn], and troubling use of influencers and celebrities to promote the product," the American Lung Association said in a statement released Jan. 16.

A 2024 National Youth Tobacco Survey suggested that only 1.8% of middle and high school students in the U.S. use nicotine pouches. However, they were still the second-most commonly used tobacco product after e-cigarettes in this demographic.

Another study, published in the journal JAMA in 2024, found that sales of nicotine pouches in the U.S. had increased by 641% between 2019 and 2022 but that only 2.9% of adults ages 18 and up reported ever using them. This raised questions as to what other groups have been using and raising the demand for these products.

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

More than 200 million people in the United States live in areas where fluoride is added to tap water. According to the most recent data available, 24 other countries around the world — including the United Kingdom, Brazil and Canada — add fluoride to their drinking water supplies, and many other jurisdictions end up ingesting fluoride via naturally occurring deposits in their water sources.

Water fluoridation has been lauded as one of the top public health achievements of the 20th century by the U.S. Centers for Disease Control and Prevention (CDC). But the practice has long been controversial, with vocal opponents arguing that the water fluoridation has adverse health or cognitive impacts.

So why do we add fluoride to water in the first place? And what do we know about its safety?

How water fluoridation began

The history of water fluoridation begins in the early 20th century, when a young dentist named Dr. Frederick McKay noticed a strange phenomenon in Colorado Springs. Residents of the town had distinctive brown, mottled stains on their teeth. Further observation revealed that, despite these notable stains, people with the "Colorado brown stain" seemed to have teeth that were unusually resistant to decay. Tooth decay, also called caries or cavities, causes holes to form in teeth.

Researchers traced the cause of the stain to the town's water supply, which contained abnormally high levels of fluoride. This finding prompted dentists to investigate whether it was possible to reap the beneficial, tooth-protecting effects of fluoridated water without experiencing the downsides of staining your teeth.

In 1945, Grand Rapids, Michigan, became the first city in the world to approve a pilot water fluoridation program. Researchers added a small amount of fluoride to the city's water supply and measured rates of tooth decay in the town's nearly 30,000 schoolchildren over the next decade. Their findings revealed that children who were born after water fluoridation began had more than 60% fewer cavities than those born prior to the program.

Related: How does fluoride prevent cavities?

The benefits of fluoridated water

Since 1945, water fluoridation has proliferated as a widespread public health practice around the world, and organizations such as the American Dental Association (ADA) stand firmly in support of water fluoridation. Many studies support the notion that water fluoridation prevents cavities in children.

"Fluoride was found to significantly reduce tooth decay," Neil Maniar, a professor of public health practice at Northeastern University, told Live Science in an email. "Putting [it] in the water supply is a form of passive prevention that can improve oral health."

Although fluoridated toothpaste has many of the same tooth-protecting properties of fluoridated water, experts say the latter comes with certain public health benefits that toothpaste lacks. That's because ingesting fluoride, rather than brushing with it, leads to more constant levels of fluoride in the mouth throughout the day, which is especially beneficial for children with developing teeth. Fluoridated water also provides a baseline level of protection for lower-income people who may not have consistent access to fluoridated toothpaste or to other forms of dental care.

"It is a way for everyone in a community to benefit from fluoride in a cost-effective manner," Maniar said. "While we often take access to a dentist and even something as simple as being able to brush teeth twice a day for granted, this is a challenge in many communities."

That was true in decades past — but some recent research is raising the question of how helpful fluoridated water is for cavity prevention.

A review of over 150 studies showed that, in recent years, water fluoridation may not be as effective at preventing cavities as it was in the 1970s, after fluoridated toothpaste became more widespread. This change may be because fluoridated toothpaste is providing enough benefit that fluoridated water no longer makes as dramatic of a difference.

However, it's important to note that the review did not include any studies from low-income countries, where fluoridated toothpaste may be less readily available. The review also notes that challenges in measuring the effects of fluoridation programs make their potential benefits difficult to quantify over time.

Is fluoridated water safe?

Both the CDC and the ADA maintain that at the levels found in the public water supply — about 0.7 mg per liter — fluoride is beneficial to public dental health and carries few documented risks.

Still, fluoride has been the focus of much safety research, and the topic continues to be a matter of public interest and controversy.

It's well known that excessive fluoride consumption can lead to fluorosis, the condition behind the "Colorado brown stain" observed by McKay in Colorado Springs. Dental fluorosis causes mottled white, yellow or brown spots and stains to appear on the teeth. But it does not compromise oral health.

Consuming even higher levels of fluoride over a long period of time can also lead to a condition called skeletal fluorosis, which compromises the integrity of the bones. This is because excessive deposits of fluoride in the skeleton causes the bones to become hard and brittle, making them more susceptible to fractures.

Both dental fluorosis and skeletal fluorosis generally occur in regions with abnormally high levels of natural fluoride deposits that leach into the water supply. Because skeletal fluorosis requires extremely high levels of fluoride exposure, it's mostly observed in regions with fluoride-contaminated groundwater, but dental fluorosis can occur due to low-level fluoride exposure through artificially fluoridated water.

Initial concerns about fluoridated water focused on whether it could cause cancer. This belief stemmed from the theory that fluoride build-up in the growth plate of the bones could lead to osteosarcoma, a type of bone cancer. While this connection is difficult to evaluate in humans, most studies have not found any strong evidence for such a link.

Does fluoride affect IQ?

More recently, concerns have been raised about the potential neurotoxic effects of fluoride.

A contentious 2024 monograph from the U.S. National Toxicology Program (NTP) looked back at dozens of studies and reported that high levels of fluoride exposure were associated with lower IQ in children. Between kids with high and low exposure levels, the average IQ difference amounted to about one or two points.

However, the levels of fluoride exposure associated with IQ changes were roughly double the levels of fluoride found in water supplies of countries like the U.S. or the U.K. — about 1.5 mg per liter. The authors also noted that, while high fluoride levels are correlated with cognitive differences in children, their results do not show that fluoride is a cause of cognitive changes.

Recently, further doubt has been cast on the studies that find a link between fluoride and decreased IQ. Reviewers at the National Academies of Science, Engineering, and Medicine pointed out major methodological and statistical problems with the NTP's monograph twice before the NTP self-published the report.

A new article that repeated the results of the NTP monograph was later published in January 2025, and researchers then pointed out that about 70% of the studies included in the meta-analysis were at high risk of bias. The association the NTP found between high levels of fluoride and IQ may not be reliable, these scientists concluded, adding that the report provided "no evidence of an adverse effect at the lower water fluoride levels" used by fluoridation programs.

Still, some researchers are continuing to investigate the minimum amount of fluoride that could potentially cause neurological effects. So far, the results are mixed — a few dozen studies have reported a relationship between aspects of cognition, such as executive function or IQ, and the levels of fluoride exposure found in artificially fluoridated water supplies. But many others have failed to replicate this link.

Many studies that tie fluoride to negative effects have been poor quality, meaning they may suffer from issues such as small sample sizes or using inconsistent or inaccurate methods. High-quality studies have been less likely to show a link between fluoride exposure and negative cognitive outcomes.

Making a determination about the safety of fluoride is challenging because when individual studies use varied methods, focus on different populations, or examine separate outcomes, it becomes difficult to compare across those studies. And because different studies find conflicting results, it's not possible to point to a single study that can prove or disprove the safety of fluoride. As a result, many experts say more high-quality research is still needed to draw a conclusion on the safety of fluoride.

"It's a very nuanced issue," Deborah Dewey, a professor of pediatrics and community health sciences at the University of Calgary and the author of a study investigating fluoride exposure and executive function in preschoolers, told Live Science. "I don't think there's a right or wrong answer right now."

Fluoride and oral health equity

Ultimately, Maniar said the conversation about fluoride really needs to be a discussion about improving oral health equity.

"Rather than focusing on fluoridation, we should be talking about the disparities that exist in oral health care, the cost burden of routine oral health care, and the significant gaps that exist related to education on oral health," Maniar said.

"The linkage between oral health and a range of serious health issues is becoming more clear every day," he said, referring to research that connects poor oral health and conditions including heart disease and pneumonia. "It's critical that we deploy all available tools to address oral health in the same manner that we would address physical and mental health."

Editor's note: This story was updated on Jan. 7, 2025 to note the publication of the NTP's meta-analysis and the resulting critiques of the research. The story was first published Dec. 28, 2024.

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

Early this month, health officials in the Democratic Republic of the Congo reported that an unknown, flu-like illness had killed dozens in the country within a few months. The World Health Organization (WHO) investigated, alongside local authorities.

Finally, on Tuesday (Dec. 17), the cause of the sicknesses was announced: severe malaria potentially complicated by malnutrition. Reuters covered the news, citing a statement from the Congo's health ministry that read, "The mystery has finally been solved." At the time, the case count was 592, with the earliest cases occurring in October.

But then, on Dec. 19, a man in the affected region died with symptoms of hemorrhagic fever, the Associated Press (AP) reported. This type of disease is typically caused by viruses — hinting that malaria and malnutrition might not be the only culprits.

As it stands, 37 deaths tied to the "mystery illness" have been confirmed in health care facilities, and additionally, 44 deaths documented in communities remain under investigation, the AP reported. Earlier estimates of the death toll ranged from 67 to 143.

Live Science spoke with experts about why the drivers behind these mystery illnesses have been so tricky to pin down.

"It's very difficult to say," said Benjamin Mordmüller, leader of the experimental medical parasitology group at Radboud University Medical Center in the Netherlands. "It could be many things."

Related: DNA from dozens of human skeletons unravels history of malaria

Challenges to diagnosis

The Congo has a high incidence of malaria, a parasitic disease spread by mosquitoes. In 2022, the most recent year with data, the country reported over 27 million infections and over 24,000 deaths from the disease. For context, across all of Africa that year, there were 233 million malaria infections and 580,000 deaths.

Although malaria is endemic to the Congo, pinpointing the disease as a culprit in the unfolding situation is a complicated task.

"It is very difficult to attribute a disease like this to malaria," said Mordmüller, who has conducted malaria research and vaccine trials in various countries, including Gabon and the Republic of Congo. "In this region, also at this time of the year, many children will have malaria parasites in the blood." On Dec. 10, WHO Director-General Dr. Tedros Adhanom Ghebreyesus noted that most of the cases and deaths have affected children under 14.

Dr. Matthew Ippolito, an associate professor of medicine at the Johns Hopkins Malaria Research Institute, works in neighboring Zambia and noted that, at any given time, about 50% of the people in areas like this are walking around with malaria parasites in their blood.

"But that doesn't mean that they have the symptoms," Mordmüller added. In places where malaria is very common, many people may not show symptoms because they have some level of existing immunity. "So they could have something else, plus parasites in the blood."

To confirm an illness is driven by malaria, you need diagnostic tests to rule out other causes. Clinically, Mordmüller said, symptomatic malaria can look a lot like other diseases, such as the flu — causing fever, headache, fatigue and chills early on. These nondescript symptoms make tests all the more important.

But as the WHO noted, "there is no functional laboratory in the health zone or province, requiring the collection and shipment of samples to Kinshasa [the nation's capital] for analysis."

The illnesses are happening in the remote Panzi health zone, located within the Kwango province in southwestern Congo. Reaching this rural area from Kinshasa takes 48 hours by road, and at this time of year, the rainy season makes the journey more difficult. Rain also boosts the number of malaria cases by increasing the number of suitable habitats for mosquitoes to lay eggs, Mordmüller added.

Complicated cases

The illnesses have been associated with coughs and runny noses; coughs are sometimes seen in malaria, but not typically runny noses. That said, "malaria can predispose you to other infections," since it strains the immune system's resources, Ippolito told Live Science. So the runny noses may stem from another disease, such as influenza.

In the deadly cases, difficulty breathing and acute malnutrition have often been observed.

Severe malaria is sometimes associated with "respiratory distress," but it's not always easy to identify the cause in places where even routine lab tests are not readily available, Ippolito said. The belabored breathing may stem from having too much acid in the blood, due to effects of the malaria parasites, or the parasites may be directly injuring lung tissue, he said.

The interaction of malnutrition with malaria is poorly understood, both Mordmüller and Ippolito said. Some studies suggest malnutrition may amplify malaria's effects, while others suggest it suppresses the symptoms. "You're not only starving the person, but you're starving the parasite as well, in a sense," Ippolito explained. So it's complicated.

The Kwango province's food insecurity worsened between spring and fall of 2024, the WHO noted. Also this year, much of southern Africa, including the Congo, experienced long dry spells, likely tied to climate change, CNN reported. Ippolito wondered how the droughts factor into the current malnutrition.

What can be done now?

Diagnostic tests and medications are now being transported to the Panzi health zone. Factors like limited mobile phone and internet network coverage complicate this effort. But assuming at least some of the diseases are caused by malaria, the medicines being deployed should help, Mordmüller said.

Given the case of hemorrhagic fever, though, a yet-unidentified virus may be another factor to contend with.

In last week's address, the WHO Director-General said, "It's possible that more than one disease is involved." Mordmüller and Ippolito echoed similar sentiments. Ultimately, time will tell what the full story is.

On Dec. 17, the National Centers for Environmental Information (NCEI) and the British Geological Survey (BGS) released an updated version of the World Magnetic Model, a prediction for how Earth's magnetic field will shift and change over the next five years.

The World Magnetic Model, which predicts the difference between magnetic north and true north at every point on Earth, plays an integral role in satellite and aircraft navigation and helps smartphone users orient themselves using services like Google Maps.

The update has been planned for years, and most users won't notice anything different as a result of the changes. But the changes are necessary to keep navigational systems functioning and to make better future predictions about Earth's magnetic field.

Why does Earth have a magnetic field?

Earth's main magnetic field is generated in the planet's outer core, a layer of molten iron 2,2001,800-3,100 miles (2,890-5,000 kilometers) below the planet's surface. The electrically conductive liquid iron is in constant motion, and when it moves through an existing weak magnetic field, that motion produces an electric current. The electric current in turn generates its own magnetic field, leading to a self-sustaining process known as the geodynamo.

Related: Earth's rotating inner core is starting to slow down — and it could alter the length of our days

The geodynamo has continually regenerated Earth's magnetic field for billions of years. Without something to sustain the field, Earth would have lost its magnetic field after about 40,000 years, said Bruce Buffett, a geophysicist at the University of California, Berkeley.

"If you had a hot cannonball and you put it on the table, it would gradually cool. [The heat] would diffuse away and essentially go back to ambient," Buffett told Live Science. "The same is true with the magnetic field. If you're not sustaining it by these fluid motions, it will gradually decay away and disappear."

Where is the magnetic north pole?

The magnetic north pole is different from the geographic North Pole, which is always stationary. The geographic North Pole is the point where Earth's axis of rotation meets the planet's surface and where all lines of longitude converge. The magnetic north pole, meanwhile, is the point in the Northern Hemisphere where Earth's magnetic field lines point directly into the planet.

The complex motion of the outer core causes the magnetic north pole to shift tens of miles per year. Because Earth's magnetic field is slightly asymmetrical and more complex than that of a regular bar magnet, the magnetic south pole — the point in the Southern Hemisphere where the magnetic field points straight into the planet — doesn't move in quite the same way. But changes in the strength of the magnetic field near the North Pole have caused it to shift from the Canadian Arctic toward Siberia in recent years.

What is the World Magnetic Model?

The World Magnetic Model is a mathematical model of Earth's magnetic field and a prediction for how the field will evolve over the next several years. The model combines data from satellites such as the European Space Agency's Swarm mission and from high-precision magnetometers at ground-based observatories to predict the magnetic field at each point on Earth.

Navigation apps use the World Magnetic Model along with GPS to orient users. "Your smartphone or GPS system has a magnetometer, effectively a digital compass built into it," said William Brown, a BGS geophysicist who helped create and update the World Magnetic Model. "It measures the direction of the magnetic field where you are, and it enters your position into the World Magnetic Model software to tell it what the magnetic field should look like. And then, by comparing what I measured and what I should have got, you can work out which direction you're facing."

Why is the World Magnetic Model being updated now?

A new version of the World Magnetic Model is released every five years to account for changes in the magnetic field from the motion of the outer core. This latest update is part of that five-year schedule.

"The real challenge is, and the reason why we release a model every five years, it doesn't change in a regular way. It's not completely predictable. It's a really complicated, chaotic system," Brown told Live Science. "Typically, about five years is when the accuracy of the model starts to get to the point where it's not as good as we would like it. So we make a better prediction with five years more information to work from, and just update the prediction going forward."

Small deviations from the predicted field can accumulate over time and occasionally compound to the point where the model must be updated more frequently. For example, the NCEI and BGS released an off-cycle update in 2019 to account for the outer core flowing faster than usual in the Northern Hemisphere — a phenomenon that caused the magnetic north pole to shift much more quickly than usual.

But for most people, the 2025 update won't result in any noticeable changes to navigation, and users won't have to change anything for phone map apps to work properly.

"You should be able to navigate as well as you could yesterday," Brown said. "We keep the updates coming so that it's only a bit of time, small enough that most people don't notice, because for most users, the accuracy is more than they need anyway."

H5N1 bird flu is spreading through poultry and cattle in the United States, and some cases have been reported in people.

No human-to-human spread of the virus has been documented, and the vast majority of infections stem from contact with farm animals. Because of this, the Centers for Disease Control and Prevention (CDC) considers the risk to the general public very low. However, a recent CDC study found that the respiratory virus is evolving to better infect mammals.

The CDC and other health agencies are keeping an eye on the virus because, if it starts spreading between people, there is the potential for a human epidemic or pandemic.

Fortunately, there are steps people can take to minimize their risk of contracting H5N1. Here's what public health agencies know about preventing bird flu infections.

Related: Bird flu could become deadlier if it mixes with seasonal flu viruses, experts warn

How do people catch H5N1?

People almost exclusively catch H5N1 through direct contact with sickened animals. The virus can travel in tiny particles, called aerosols, through the air, as well as through slightly larger "respiratory droplets" and possibly on bits of dust, according to the CDC. These particles are shed when animals breathe, excrete waste, or — for cows — during milking.

The viral particles can cause infection when they enter a person's eyes, nose or mouth, either when the person breathes or touches their face after their hands have been contaminated.

There have been a handful of cases this year — two in the U.S. and one in Canada — in which someone has contracted H5N1 without known contact with livestock or wild birds. Public health officials aren't sure how the virus was transmitted in these cases. Avian flu can also be transmitted through wild bird droppings, so it's possible these individuals encountered the virus outdoors without actually getting close to a sickened animal.

Has H5N1 infected people before?

The H5N1 subtype of avian flu was first detected in wild waterfowl in southern China in 1996, and it caused scattered outbreaks among domestic poultry in the region in 1997, according to the CDC. Since then, there have been more than 900 sporadic human cases around the world. Half of the people infected died, raising fears about the seriousness of the disease.

In 2005, the disease spread to Africa, the Middle East and Europe, although it was still mostly affecting animals. In 2021, a new genetic subtype of the virus emerged and quickly spread to the Americas. There, it sparked deadly outbreaks among commercial poultry, and recently, it's infected goats, dairy cows and the occasional person.

As of Nov. 26, there have been 55 confirmed cases of bird flu among people in the United States in 2024, according to the CDC. All but two of these cases are known to have involved direct contact with cattle or poultry. In California, the state with the most reported cases, 28 out of 29 infected people caught the flu by working with cattle.

The two remaining U.S. cases had no known animal source: one in a child in California and one in an adult in Missouri. A teenager in British Columbia also recently fell ill with no known animal contacts. In none of these cases has the disease spread to other people, according to the CDC. Officials suspect animals were also the source of these individuals' infections, although they haven't been able to pinpoint the exact route of exposure.

Who's at risk of catching bird flu?

Farmworkers and other people whose work brings them in close contact with poultry and cattle face the highest risk of bird flu. A recent study found that the virus can remain infectious in raw milk and on milking equipment for more than an hour, meaning milk could be a source of exposure for dairy workers. Workers may also become ill while cleaning droppings from poultry pens.

There are concerns that raw milk consumption could raise the risk of transmission to people beyond the agricultural industry. Additionally, because wild animals can carry H5N1, there's some risk of people becoming exposed through interactions with infected animals or via exposure to their feces, respiratory fluids or contaminated fur.

How can you avoid catching bird flu?

The CDC has issued guidance for the use of personal protective equipment (PPE) for farmworkers. This PPE includes respirators, a type of face mask, to prevent people from breathing in the virus and safety goggles to keep the virus out of their eyes.

Members of the general public can protect themselves by avoiding close contact with sickly or dead animals, according to the CDC. Unusual or suspicious cases of animal death can be reported to the local health department or state wildlife agency.

There have been no known cases of transmission of avian flu from the commercial food supply in the U.S., but raw poultry products have previously caused infections in southeast Asia, the CDC says. As a general food safety measure, the CDC recommends cooking poultry and eggs to an internal temperature of 165 degrees Fahrenheit (73.9 degrees Celsius). Ground beef should be cooked to 160 F (71.1 C) and whole cuts of beef should reach 145 degrees F (62.8 C).

Raw milk and products made from raw milk, such as yogurt, should be avoided, the CDC cautions. Raw milk not only poses potential risks due to avian flu but also carries known risks of other contamination, such as Listeria bacteria.

Is there a vaccine for bird flu?

There is no vaccine against H5N1 avian flu currently available, given that the disease still does not easily spread between people.

However, given the possibility that the virus could one day evolve to enable human-to-human transmission, the U.S. government has developed five candidate virus proteins as the basis for future vaccines. Federal health officials have also ordered the production of 4.8 million doses of an experimental bird flu vaccine to have on hand in case of human-to-human transmission or any other concerning change in how the virus operates.

Recent research also suggests that vaccines based on earlier genetic subtypes of H5N1 can still protect against the most recently emerged version of the virus.

In addition, earlier this year, the Argentinian vaccine manufacturer Sinergium Biotech launched a project with World Health Organization support to use mRNA — the genetic molecule used in some COVID-19 vaccines — to develop vaccines against H5N1. The goal is to ensure that low- and middle-income countries will be prepared for potential pandemics, despite lacking resources for vaccine programs of their own.

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 strange weather phenomenon known as a DANA has caused catastrophic flash flooding in Valencia, Spain, this week. More than 155 people have died and dozens remain missing in what meteorologists are calling one of the worst natural disasters in recent memory.

On Tuesday (Oct. 29), some areas received the equivalent of a year's worth of rainfall in just a few hours, triggering massive floods that devastated entire towns and left thousands of people stranded. In some areas, rainfall reached up to 20 inches of rainfall (500 liters per square meter).

The cause of this disastrous weather is a phenomenon that forms in the Mediterranean called a Depresión Aislada en Niveles Altos (DANA),a Spanish phrase that translates to isolated depression at high levels. It was the most severe DANA recorded in the 21st century, comparable to the catastrophic "Pantanada de Tous" in 1982, according to Spain's State Meteorological Agency (Aemet).

What is a DANA?

DANAs are intensified versions of what's known as a "cold drop," which occurs when a mass of warm air collides with a stagnant mass of cold air at an altitude of around 29,500 feet (9,000 meters).

In the upper atmosphere, there is a very strong wind current that surrounds Earth like a belt. Sometimes, this current begins to oscillate, appearing more like a snake than a belt. When this happens, the oscillation can get "stuck," enabling the mass of cold air to remain in one place. On this occasion, it happened over southeast Spain.

A DANA occurs when this cold air meets very warm air near the surface, especially above the warm waters of the Mediterranean. This combination creates a significant temperature difference between the different layers of the atmosphere, which in turn causes the warm air to rise easily and become saturated with water vapor.

If this temperature contrast is combined with humidity and energy from the Mediterranean, which is very warm after the summer months, the result is heavy storms and torrential rain.

"The winds may not be as violent as those of a hurricane, but in terms of rainfall and intensity, they can even surpass them. These events can cause material damage and loss of life as significant as those of an average hurricane," Jorge Olcina, director of the Climatology Laboratory at the University of Alicante, told Live Science.

Iago Pérez, a geoscientist at the University of Oxford, described DANAs as one of the most dangerous meteorological phenomena in Spain, noting that "they release enormous quantities of water in a very short time."

DANAs form only over Spain, but similar weather patterns, called extratropical cyclones, form in the Atlantic off Uruguay and Argentina, the researchers said.

On Oct. 29, the DANA hovered over the same area for more than 12 hours, making it the most intense day of the weather event — which is expected to continue with less intensity until Sunday (Nov. 3).

DANAs use warm water as "fuel," meteorologist Mar Gómez told Live Science.

The DANA encountered water temperatures around 72 degrees Fahrenheit (22 degrees Celsius) off the coast of Valencia, while the usual temperature for this time of year is around 70 F (21 C). That difference may seem small, but it is enough to supply the storm system with extra energy. This can "trigger a cascade of rainfall in a very short period," Olcina said."These rains can be characterized as monsoonal."

What does climate change have to do with it?

Gómez and Olcina agree that the severity of this week's DANA is directly related to climate change. Pérez, however, thinks pinning the phenomenon on global warming requires deeper analysis.

The Mediterranean Sea is one of the marine basins that has warmed the most in recent decades. It acts as a "transmission belt for humidity and energy," Olcina said. Since the 1980s, the average temperature of the Mediterranean has increased by 2.7 F (1.5 C) — almost double the rise in air temperature in the region over the same period. "Since 2020, summers on the Iberian Peninsula have seen record temperatures, and this year, sea surface temperatures have exceeded 84.2 F [29 C]" Olcina said.

This warming has altered the timing of DANAs, as the Mediterranean now begins to heat up in May and retains that warmth through November. In comparison, during the 1980s and 1990s, this phenomenon generally occurred in September and October. Currently, an estimated 15% to 20% more DANAs form each year compared with six decades ago.

For researchers, this episode offers important lessons, beginning with the need to improve early warning communication protocols.

"When there are fatalities, it means that something has gone wrong. Communication and anticipation of these events must be enhanced," Gómez stated.

Climate change will likely fuel more frequent intense and exceptional precipitation events. This underscores the urgent need to adapt prevention and protection systems and to restructure vulnerable areas to reduce risks associated with an increasingly extreme climate, Olcina said.

NASA has successfully launched the Europa Clipper, the agency's biggest-ever interplanetary spacecraft, into space and it's now headed for Jupiter's frozen moon Europa.

"Congratulations to our Europa Clipper team for beginning the first journey to an ocean world beyond Earth," NASA Administrator Bill Nelson said in a statement.

The craft took off Oct. 14 on top of a SpaceX Falcon Heavy rocket from NASA's Kennedy Space Center in Florida. It was originally slated to launch Oct. 10, but the mission was pushed back because of Hurricane Milton, which smashed into Florida Oct. 9.

When the Europa Clipper arrives in 2030, the orbiter will study the frozen moon's hidden ocean, which is locked beneath an icy shell, to determine how habitable the ocean is and whether it could potentially support life.

Related: Jupiter's moon Europa lacks oxygen, making it less hospitable for sustaining life

How big is the Europa Clipper?

Once it spreads its solar arrays, the orbiter will measure around 100 feet (30 meters) wide — bigger than a basketball court. It is about 16 feet (5 m) high, according to NASA. The giant arrays are needed to collect solar energy to power the craft when it arrives at Europa, which is about 470 million miles (760 million kilometers) from the sun.

How long will it take the Europa Clipper to reach Jupiter?

The craft will take 5.5 years and travel 1.8 billion miles (2.9 billion km) to Jupiter's fourth-largest moon, according to NASA's Jet Propulsion Laboratory (JPL). It will swing close to Mars for a "gravity assist" in February 2025, before heading back to Earth to slingshot around our planet in December 2025 to make its way to Jupiter. It will reach the colossal planet and its moons in June 2030.

Once there, the orbiter will perform flybys around several of Jupiter's moons, before making its first pass of Europa in spring 2031. In total, the craft will perform 49 flybys of Europa.

What is the purpose of Europa Clipper?

Europa Clipper's mission is to peer beneath Europa's frozen surface to look for key signs of habitable conditions. These are water, organics — essential chemical building blocks — chemical energy sources under the surface, and signs of stable conditions, according to NASA.

Scientists believe that Europa has a vast saltwater ocean that holds twice as much water as Earth's oceans — even though the moon is just one-quarter the size of our planet. Because of this water, scientists consider Europa one of the likeliest places in the solar system to find habitable conditions. Scientists still aren't sure how thick the icy shell is, so one of Europa's main scientific aims is to determine this and work out the composition of the ice and the vast ocean beneath it, according to NASA.

The findings could give scientists clues about where to spot potential life across the universe.

"By exploring the unknown, Europa Clipper will help us better understand whether there is the potential for life not just within our solar system, but among the billions of moons and planets beyond our Sun," Nelson noted.

However, Europa Clipper will not look directly for signs of alien life in the moon's ocean.

How much does Europa Clipper cost?

Europa Clipper cost about $3.8 billion to make and launch, and it will cost another $1.2 billion to operate until it completes its core mission in 2034, according to the Planetary Society. The spacecraft is carrying a collection of advanced equipment, which accounts for some of this cost. The nine instruments include an array of cameras to view the moon in visible light and infrared; a spectrometer and spectrograph to reveal Europa's composition; instruments to monitor gravity, magnetic fields and plasma; radar to peer beneath the surface; and instruments to perform chemical analysis.

The instruments are encased in a vault lined with aluminum and titanium to protect them from the extremely high levels of radiation around Jupiter, according to NASA. These radiation levels are the second-highest in the entire solar system — second only to the sun, according to JPL.

Will Europa clipper land on Europa?

The spacecraft will not land on Europa. Instead, it will stay in an elliptical orbit around Jupiter, which will help it survive the radiation levels that exist closer to Jupiter and Europa. At the end of its life, Europa Clipper will likely "deorbit," meaning deliberately crash, into the surface of Ganymede — Jupiter's and the solar system's largest moon.

In the coming weeks, NASA will launch a hotly anticipated new mission to Jupiter's fourth-largest moon, Europa.

Called Europa Clipper, the spacecraft will conduct a detailed study of the moon, looking for potential places where Europa might host alien life. (The launch window for the mission begins Oct. 10, but the launch has been temporarily postponed due to the impending landfall of Hurricane Milton.)

Europa Clipper is the largest planetary exploration spacecraft NASA has ever made: as wide as a basketball court when its solar sails are unfolded. It has a mass of about 6,000 kilograms — the weight of a large African elephant.

But why are we sending a hulking spacecraft all the way to Europa?

Looking for life away from Earth

The search for life in places other than Earth usually focuses on our neighbour Mars, a planet that's technically in the "habitable zone" of our Solar System. But Mars is not an attractive place to live, due to its lack of atmosphere and high levels of radiation. However, it's close to Earth, making it relatively easy to send missions to explore it.

But there are other places in the Solar System that could support life — some of the moons of Jupiter and Saturn. Why? They have liquid water.

Here on Earth, water is the solvent of life: water dissolves salts and sugars, and facilitates the chemical reactions needed for life on Earth to proceed. It's possible life forms exist elsewhere that rely on liquid methane or carbon dioxide or something else, but life as we know it uses water.

The reason there's liquid water so far out in the Solar System is because Jupiter and Saturn, the gas giants, wield immense gravitational power over their moons.

Saturn's moons, Titan and Enceladus, are stretched and compressed by gravity as they go around their host planet. This movement results in vast underground oceans with a surface of solid ice, with plumes of water vapour exploding 9,600 kilometres from the surface.

It is strongly suspected that Europa is the same. While we know a lot about Europa from more than four centuries of observation, we have not confirmed it has an under-ice liquid ocean like Titan and Enceladus.

Related: Jupiter's moon Europa lacks oxygen, making it less hospitable for sustaining life

But all clues point to yes. Europa has a smooth surface despite being hit by many meteors, suggesting the surface is young, recently replaced. Ice volcanoes raining down water over the surface would make sense.

It also has a magnetic field, suggesting that like Earth, Europa has a liquid layer inside (on Earth, this liquid is molten rock).

What will Europa Clipper do?

At the surface, Europa is bombarded by high levels of space radiation, concentrated by Jupiter. But deeper down, the thick ice sheet could be protecting life in the liquid subsurface ocean.

This means it would be difficult for us to find concrete evidence for life without drilling down deep. But where to look? Through flybys of the icy moon, Europa Clipper will be looking at areas where life could be dwelling under the icy shell.

To achieve this, Europa Clipper has nine scientific instruments. These include a wide-angle camera to study geologic activity and a thermal imaging system to measure surface texture and detect warmer regions on the surface.

There's also a spectrometer for looking at the chemical composition of the gases and surface of Europa, and for any explosive plumes of water from the surface. The mission also has tools for mapping the moon's surface.

Other instruments will measure the depth and salt levels of the moon's ocean and the thickness of its ice shell, and also how Europa flexes within the strong gravitational pull of Jupiter.

Excitingly, a mass spectrometer will analyze the gases of the moon's faint atmosphere and potential plumes of water. By examining the material ejected from the plumes, we can understand what is hidden within the under-ice oceans of Europa.

A dust analyser will also look at matter that has been ejected from Europa's surface by tiny meteorites or released from the plumes.

Unfortunately, we will have to wait a while for any discoveries. Europa Clipper will take more than five years to reach Jupiter. And the mission is only equipped to look for the potential of life, not life itself. If we see evidence that might point towards life, we will need future missions to return and explore Europa in depth.

So we must be patient. But this is an exciting opportunity for humanity to get one step closer to find life beyond our own home planet.

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

Antarctica's Thwaites Glacier got its nickname the "Doomsday Glacier" for its potential to flood coastlines around the world if it collapsed. It is already contributing about 4% of annual sea-level rise as it loses ice, and one theory suggests the glacier could soon begin to collapse into the ocean like a row of dominoes.

But is that kind of rapid collapse really as likely as feared? A new study of Thwaites Glacier's susceptibility to what's known as marine ice cliff instability offers some hope. But the findings don't mean Thwaites is stable.

Polar scientist Mathieu Morlighem, who led the study, explains the results.

Why is the Thwaites Glacier so important?

Thwaites Glacier drains a huge area of Antarctica's ice sheet — about 74,000 square miles (192,000 square kilometers), an expanse bigger than Florida. If a snowflake falls within that drainage system, it will eventually end up as part of an iceberg in the ocean off Thwaites.

What we are seeing with Thwaites Glacier right now is a disaster in slow motion.

The bedrock under Thwaites Glacier sits below sea level and slopes downward going inland, so the glacier gets deeper toward the interior of the ice sheet. Once the glacier begins losing more ice than it gains from new snowfall and starts to retreat, it's very hard to slow it down because of this slope. And Thwaites is already retreating at an accelerating rate as the climate warms.

Related: 'We were in disbelief': Antarctica is behaving in a way we've never seen before. Can it recover?

Thwaites Glacier holds enough ice to raise global sea level by more than 2 feet (0.65 meters). Once Thwaites starts to destabilize, it also will destabilize neighboring glaciers. So, what happens to Thwaites affects all of the West Antarctic Ice Sheet, and that affects sea-level rise along coastlines everywhere.

What is marine ice cliff instability?

Marine ice cliff instability is a relatively new concept proposed by scientists in the past decade.

Many of the glaciers around Antarctica have huge floating extensions called ice shelves that buttress the glacier and slow its ice flow into the ocean. With the climate warming, we have seen some of these floating extensions collapse, sometimes very rapidly, in the span of a few weeks or months.

If Thwaites' ice shelf were to collapse, it would expose a very tall ice cliff facing the ocean along its 75-mile (120-kilometer) front. There is only so much force that ice can sustain, so if the cliff is too tall, it will collapse into the ocean.

Once that happens, a new ice cliff farther back would be exposed, and the new cliff would be even taller because it is farther inland. The theory of marine ice cliff instability suggests that if the cliffs collapse quickly enough, that could have a domino effect of ever-higher ice cliffs collapsing one after the other.

However, no one has observed marine ice cliff instability in action. We don't know if it will happen, because a lot depends on how quickly the ice collapses.

What did you discover about the risk to Thwaites?

When the theory of marine ice cliff instability was first introduced, it used a rough approximation of how ice cliffs might collapse once the ice shelf was gone.

Studies since then have determined that ice cliffs won't fail systematically until the ice is about 442 feet (135 meters) high. Even at that point, they would fail more slowly than projected until they became much taller.

We used three high-resolution models to explore what this new physical understanding of ice cliff instability would mean for Thwaites Glacier this century.

Our results show that if Thwaites' entire ice shelf collapsed today, its ice front would not rapidly retreat inland due to marine ice cliff instability alone. Without the ice shelf, the glacier's ice would flow much faster toward the ocean, thinning the front of the glacier. As a result, the ice cliffs wouldn't be as high.

We found that Thwaites would remain fairly stable at least through 2100. We also simulated an ice shelf collapse in 50 years, when the glacier's grounding line — where its grounded ice meets the ocean — would have retreated deeper inland. Even then, we found that marine ice cliff instability alone would not cause a rapid retreat.

The results call into question some recent estimates of just how fast Thwaites might collapse. That includes a worst-case scenario that the Intergovernmental Panel on Climate Change mentioned in its latest assessment report but labeled as "low likelihood."

Thwaites is the glacier everyone is worried about. If you model the entire ice sheet, this is where marine ice cliff instability starts and where it propagates far inland. So, if Thwaites isn't as vulnerable to ice cliff failure as we thought, that's a good sign for the entire ice sheet.

But marine ice cliff instability is only one mechanism of ice loss. This finding doesn't mean Thwaites is stable.

What else is causing glaciers to retreat at an accelerating rate?

There are many processes that make the Antarctic ice sheet unstable, some of them very well understood.

Ice-ocean interactions explain most of the recent ice mass loss so far. Antarctica is a very cold place, so atmospheric warming isn't having a large effect yet. But warm ocean currents are getting under the ice shelves, and they are thinning the ice from below, which weakens the ice shelves. When that happens, the ice streams flow faster because there is less resistance.

Over the past few decades, the Amundsen Sea sector, where Thwaites and Pine Island glaciers are located, has seen an intrusion of warm water from the Antarctic Circumpolar Current, which has been melting the ice from below.

What does climate change have to do with it?

Antarctica can seem like a faraway place, but human activities that warm the planet — such as burning fossil fuels — are having dramatic effects at the poles. Ice loss contributes to sea-level rise, affecting coastal regions around the world.

People's choices today will determine how quickly the water rises.

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

Two astronauts marooned in space may sound like the plot of a Hollywood blockbuster, but for two NASA crew members, it is now a reality. Commander Barry Wilmore and pilot Sunita Williams are currently in limbo on the International Space Station (ISS).

They arrived in the Boeing Starliner spacecraft — the first test of the spaceship with astronauts. Wilmore and Williams were supposed to stay on the ISS for around eight days and return on the same spacecraft. But there is now debate about the safety of Starliner after it experienced helium leaks and thruster problems on its way to the ISS.

In coming days, Nasa and Boeing may decide to clear Starliner to carry the astronauts back to Earth. This means their stay might not last too much longer. But if officials decide against Starliner, the astronauts face waiting an additional six months in orbit before returning. So how do astronauts cope with a potential six-month wait for a lift home?

Waiting for things is difficult at the best of times. Under normal circumstances, it is frustrating, stressful and anxiety-provoking. But in extreme situations, with high stakes, waiting can be purgatory.

Part of the reason that waiting is difficult is that it distorts our sense of time. Think of last time you were waiting for a delayed train, test results or a text from a potential new partner. Did it fly by or drag? For most people, time spent waiting crawls at a glacial pace. As a result, delays and periods of anticipation often feel much longer than they actually are.

Waiting slows our perception of time, because it changes the amount of time that we spend thinking about time. During normal daily life we often ignore time; our brains have a limited capacity. If time isn't important, we simply don't think about it, and this helps it to pass quickly.

Related: Why time seems to fly by

When we are waiting, our desire to know when the wait is over increases how much we think about time. This "clock watching" can make the minutes and hours feel like they are passing at a snail's pace. Stress, discomfort and pain exacerbate this effect, meaning that waiting in difficult situations can seem even longer.

Waiting also slows our perception of time because it influences what we do and how we feel. Normal life is busy and full of ever-changing activities and interactions. The sudden need to wait halts the flow of life, often leaving us with nothing else to do, thus increasing levels of boredom and frustration.

In general, time filled with activity passes more quickly. We all got a taste of this during COVID lockdowns. When we were stuck inside unable to see friends and engage in normal daily activities, the loss of routine and distractions caused time to drag for many.

For the astronauts stuck on the ISS, anxiety about when they will return, limited opportunities for activities and fewer opportunities to contact friends and families combine to make their wait to return home feel significantly longer than six months — if it should come to that.

However, as academics who research the effects of time on human psychology and biology, our ongoing work with crew members at research stations in Antarctica aims to shed light on whether waiting in extreme environments is different to waiting during normal daily life.

A year in Antarctica

While being stuck for six months on the ISS may sound like many people's worst nightmare, it is not uncommon for scientists to spend long periods isolated and confined in extreme environments. Every year, organisations such as the Instituto Antártico Argentino (which uses the Belgrano II Antarctic station), the French Polar Institute and the Italian Antarctic Programme, in cooperation with the European Space Agency (which all use Antarctica's Concordia station), send crews of people for up to 16 months to conduct research on the frozen continent.

During the March to October polar winter, teams spend six months in near darkness — and from May to August, in complete darkness — facing outside temperatures of up to -60C, wind speeds of 160 km/h (100 mph) and storms which prevent almost all outdoor activity. Limited internet coverage can also prevent constant communication with the outside world.

For the last year, we have researched how life in Antarctica influences people's experience of time. Each month, we asked crew members how time felt like it was passing in comparison to before their mission. Trapped on base, with limited contact with the outside world, you might expect time to drag. However, our results suggest the opposite may be true.

Analysis of crew members' experiences indicated that being constantly busy with complex tasks such as scientific research helped time to pass swiftly, according to 80% of crew responses. Only 3% of responses indicated that time actually dragged, and these reports occurred when nights were long and there was little to do.

These experiences may provide hope for those stuck on the ISS. Like life on an Antarctic station, these Nasa astronauts have a busy and mentally demanding existence. These factors may help time to pass quickly.

However, a key factor of their wait may be their ability to tolerate the uncertainty of when they will return. Wilmore and Williams will spend their time in a space equivalent to the inside a Boeing 747 plane. But better information about "when" things will happen and "why" delays are being incurred can help people to tolerate waiting and reduce its impact on their wellbeing.

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

Last week, a huge solar flare sent a wave of energetic particles from the Sun surging out through space. Over the weekend, the wave reached Earth, and people around the world enjoyed the sight of unusually vivid aurora in both hemispheres.

While the aurora is normally only visible close to the poles, this weekend it was spotted as far south as Hawaii in the northern hemisphere, and as far north as Mackay in the south.

This spectacular spike in auroral activity appears to have ended, but don’t worry if you missed out. The Sun is approaching the peak of its 11-year sunspot cycle, and periods of intense aurora are likely to return over the next year or so.

If you saw the aurora, or any of the photos, you might be wondering what exactly was going on. What makes the glow, and the different colours? The answer is all about atoms, how they get excited – and how they relax.

When electrons meet the atmosphere

The auroras are caused by charged subatomic particles (mostly electrons) smashing into Earth’s atmosphere. These are emitted from the Sun all the time, but there are more during times of greater solar activity.

Most of our atmosphere is protected from the influx of charged particles by Earth’s magnetic field. But near the poles, they can sneak in and wreak havoc.

Earth’s atmosphere is about 20% oxygen and 80% nitrogen, with some trace amounts of other things like water, carbon dioxide (0.04%) and argon.

When high-speed electrons smash into oxygen molecules in the upper atmosphere, they split the oxygen molecules (O₂) into individual atoms. Ultraviolet light from the Sun does this too, and the oxygen atoms generated can react with O₂ molecules to produce ozone (O₃), the molecule that protects us from harmful UV radiation.

But, in the case of the aurora, the oxygen atoms generated are in an excited state. This means the atoms’ electrons are arranged in an unstable way that can “relax” by giving off energy in the form of light.

What makes the green light?

As you see in fireworks, atoms of different elements produce different colours of light when they are energised.

Copper atoms give a blue light, barium is green, and sodium atoms produce a yellow–orange colour that you may also have seen in older street lamps. These emissions are “allowed” by the rules of quantum mechanics, which means they happen very quickly.

When a sodium atom is in an excited state it only stays there for around 17 billionths of a second before firing out a yellow–orange photon.

But, in the aurora, many of the oxygen atoms are created in excited states with no “allowed” ways to relax by emitting light. Nevertheless, nature finds a way.

The green light that dominates the aurora is emitted by oxygen atoms relaxing from a state called “¹S” to a state called “¹D”. This is a relatively slow process, which on average takes almost a whole second.

In fact, this transition is so slow it won’t usually happen at the kind of air pressure we see at ground level, because the excited atom will have lost energy by bumping into another atom before it has a chance to send out a lovely green photon. But in the atmosphere’s upper reaches, where there is lower air pressure and therefore fewer oxygen molecules, they have more time before bumping into one another and therefore have a chance to release a photon.

For this reason, it took scientists a long time to figure out that the green light of the aurora was coming from oxygen atoms. The yellow–orange glow of sodium was known in the 1860s, but it wasn’t until the 1920s that Canadian scientists figured out the auroral green was due to oxygen.

What makes the red light?

The green light comes from a so-called “forbidden” transition, which happens when an electron in the oxygen atom executes an unlikely leap from one orbital pattern to another. (Forbidden transitions are much less probable than allowed ones, which means they take longer to occur.)

However, even after emitting that green photon, the oxygen atom finds itself in yet another excited state with no allowed relaxation. The only escape is via another forbidden transition, from the ¹D to the ³P state — which emits red light.

This transition is even more forbidden, so to speak, and the ¹D state has to survive for about about two minutes before it can finally break the rules and give off red light. Because it takes so long, the red light only appears at high altitudes, where the collisions with other atoms and molecules are scarce.

Also, because there is such a small amount of oxygen up there, the red light tends to appear only in intense auroras — like the ones we have just had.

This is why the red light appears above the green. While they both originate in forbidden relaxations of oxygen atoms, the red light is emitted much more slowly and has a higher chance of being extinguished by collisions with other atoms at lower altitudes.

Other colours, and why cameras see them better

While green is the most common colour to see in the aurora, and red the second most common, there are also other colours. In particular, ionised nitrogen molecules (N₂⁺, which are missing one electron and have a positive electrical charge), can emit blue and red light. This can produce a magenta hue at low altitudes.

All these colours are visible to the naked eye if the aurora is bright enough. However, they show up with more intensity in the camera lens.

There are two reasons for this. First, cameras have the benefit of a long exposure, which means they can spend more time collecting light to produce an image than our eyes can. As a result, they can make a picture in dimmer conditions.

The second is that the colour sensors in our eyes don’t work very well in the dark —  so we tend to see in black and white in low light conditions. Cameras don’t have this limitation.

Not to worry, though. When the aurora is bright enough, the colours are clearly visible to the naked eye.

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

The word "leprosy" conjures images of biblical plagues, but the disease is still with us today. Caused by infectious bacteria, some 200,000 new cases are reported each year, according to the World Health Organization. In the United States, leprosy has been entrenched for more than a century in parts of the South where people came into contact with armadillos, the principle proven linkage from animal to humans. However, the more recent outbreaks in the Southeast, especially Florida, have not been associated with animal exposure.

The Conversation talked with Robert A. Schwartz, professor and head of dermatology at Rutgers New Jersey Medical School, to explain what researchers know about the disease.

What is leprosy and why is it resurfacing in the U.S.?

Leprosy is caused by two different but similar bacteria — Mycobacterium leprae and Mycobacterium lepromatosis — the latter having just been identified in 2008. Leprosy, also known as Hansen's disease, is avoidable. Transmission among the most vulnerable in society, including migrant and impoverished populations, remains a pressing issue.

This age-old neglected tropical disease, which is still present in more than 120 countries, is now a growing challenge in parts of North America.

Leprosy is beginning to occur regularly within parts of the southeastern United States. Most recently, Florida has seen a heightened incidence of leprosy, accounting for many of the newly diagnosed cases in the U.S.

The surge in new cases in central Florida highlights the urgent need for health care providers to report them immediately. Contact tracing is critical to identifying sources and reducing transmission.

Traditional risk factors include zoonotic exposure and having recently lived in leprosy-endemic countries. Brazil, India and Indonesia have each noted more than 10,000 new cases since 2019, according to the World Health Organization data, and more than a dozen countries have reported between 1,000 to 10,000 new cases over the same time period.

Why was leprosy stigmatized in biblical times?

Evidence suggests that leprosy has plagued civilization since at least the second millennium B.C.

From that time until the mid-20th century, limited treatments were available, so the bacteria could infiltrate the body and cause prominent physical deformities such as disfigured hands and feet. Advanced cases of leprosy cause facial features resembling that of a lion in humans.

Many mutilating and distressing skin disorders such as skin cancers and deep fungal infections were also confused with leprosy by the general public.

Fear of contagion has led to tremendous stigmatization and social exclusion. It was such a serious concern that the Kingdom of Jerusalem had a specialized hospital to care for those suffering from leprosy.

How infectious is leprosy?

Research shows that prolonged in-person contact via respiratory droplets is the primary mode of transmission, rather than through normal, everyday contact such as embracing, shaking hands or sitting near a person with leprosy. People with leprosy generally do not transmit the disease once they begin treatment.

Armadillos represent the only known zoonotic reservoir of leprosy-causing bacteria that threaten humans. These small mammals are common in Central and South America and in parts of Texas, Louisiana, Missouri and other states, where they are sometimes kept as pets or farmed as meat. Eating armadillo meat is not a clear cause of leprosy, but capturing and raising armadillos, along with preparing its meat, are risk factors.

The transmission mechanism between zoonotic reservoirs and susceptible individuals is unknown, but it is strongly suspected that direct contact with an infected armadillo poses a significant risk of developing leprosy. However, many cases reported in the U.S. have demonstrated an absence of either zoonotic exposure or person-to-person transmission outside of North America, suggesting that transmission may be happening where the infected person lives. But in many cases, the source remains an enigma.

Some people's genetics might make them more susceptible to leprosy infections, or their immune systems are less capable of resisting the disease.

Stigma and discrimination have prevented people from seeking treatment, and as a result, "concealed" cases contribute to transmission.

How do you recognize it?

Leprosy primarily affects the skin and peripheral nervous system, causing physical deformity and desensitizing one's ability to feel pain on affected skin.

It may begin with loss of sensation on whitish patches of skin or reddened skin. As the bacteria spread in the skin, they can cause the skin to thicken with or without nodules. If this occurs on a person's face, it may rarely produce a smooth, attractive-appearing facial contour known as lepra bonita, or "pretty leprosy." The disease can progress to causing eyebrow loss, enlarged nerves in the neck, nasal deformities and nerve damage.

The onset of symptoms can sometimes take as long as 20 years because the infectious bacteria have a lengthy incubation period and proliferate slowly in the human body. So presumably many people are infected long before they know that they are.

Fortunately, worldwide efforts to screen for leprosy are being enhanced thanks to organizations like the Order of Saint Lazarus, which was originally founded in the 11th century to combat leprosy, and the Armauer Hansen Research Institute, which conducts immunologic, epidemiological and translational research in Ethiopia. The nongovernmental organization Bombay Leprosy Project in India does the same.

How treatable is it?

Leprosy is not only preventable but treatable. Defying stigma and advancing early diagnosis via proactive measures are critical to the mission of controlling and eradicating it worldwide.

Notably, the World Health Organization and other agencies provide multi-drug therapy at no cost to patients.

In addition, vaccine technology to combat leprosy is in the clinical trials stage and could become available in coming years. In studies involving nine-banded armadillos, this protein-based vaccine delayed or diminished leprous nerve damage and kept bacteria at bay. Researchers believe that the vaccine can be produced in a low-cost, highly efficient manner, with the long-term prospect of eradicating leprosy.

If health care professionals, biomedical researchers and lawmakers do not markedly enhance their efforts to eliminate leprosy worldwide, the disease will continue to spread and could become a far more serious problem in areas that have been largely free of leprosy for decades.

The World Health Organization launched a plan in 2021 for achieving zero leprosy.

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

In the past decade, lab-grown blobs of human brain tissue began making news headlines, as they ushered in a new era of scientific discovery and raised a slew of ethical questions.

These blobs — scientifically known as brain organoids, but often called "minibrains" in the news — serve as miniature, simplified models of full-size human brains. These organoids can potentially be useful in basic research, drug development and even computer science.

However, as scientists make these models more sophisticated, there's a question as to whether they could ever become too similar to human brains and thus gain consciousness, in some form or another.

How are minibrains made? 

Scientists typically grow brain organoids from stem cells, a type of immature cell that can give rise to any cell type, whether blood, skin, bowel or brain.

The stem cells used to grow organoids can either come from adult human cells, or more rarely, human embryonic tissue, according to a 2021 review in the Journal of Biomedical Science. In the former case, scientists collect adult cells and then expose them to chemicals in order to revert them into a stem cell-like state. The resulting stem cells are called "induced pluripotent stem cells" (iPSC), which can be made to grow into any kind of tissue.

To give rise to a minibrain, scientists embed these stem cells in a protein-rich matrix, a substance that supports the cells as they divide and form a 3D shape. Alternatively, the cells may be grown atop a physical, 3D scaffold, according to a 2020 review in the journal Frontiers in Cell and Developmental Biology.

To coax the stem cells to form different tissues, scientists introduce specific molecules and growth factors — substances that spur cell growth and replication — into the cell culture system at precise points in their development. In addition, scientists often place the stem cells in spinning bioreactors as they grow into minibrains. These devices keep the growing organoids suspended, rather than smooshed against a flat surface; this helps the organoids absorb nutrients and oxygen from the well-stirred solution surrounding them.

Brain organoids grow more complex as they develop, similar to how human embryos grow more and more complex in the womb. Over time, the organoids come to contain multiple kinds of cells found in full-size human brains; mimic specific functions of human brain tissue; and show similar spatial organization to isolated regions of the brain, though both their structure and function are simpler than that of a real human brain, according to the Journal of Biomedical Science review.

Although most brain organoids are grown from stem cells, in 2023, a study published in the journal Cell demonstrated that it is also possible to grow them directly from human fetal tissue. Unlike stem-cell-derived organoids, these minibrains don't require scaffolding proteins to support their growth and may be able to more accurately capture brain tissues at specific stages of development, the study authors said.

Why are scientists growing minibrains? 

Minibrains can be used in a variety of applications. For example, scientists are using the blobs of tissue to study early human development.

To this end, scientists have grown brain organoids with a set of eye-like structures called "optic cups;" in human embryos in the womb, the optic cup eventually gives rise to the light-sensitive retina at the back of the eye. Another group grew organoids that generate brain waves similar to those seen in preterm babies, and another used minibrains to help explain why a common drug can cause birth defects and developmental disorders if taken during pregnancy. Models like these allow researchers to glimpse the brain as it appears in early pregnancy, a feat that would be both difficult and unethical in humans.

Minibrains can also be used to model conditions that affect adults, including infectious diseases that affect the brain, brain tumors and neurodegenerative disorders like Alzheimer's and Parkinson's disease, according to the Frontiers in Cell and Developmental Biology review. In addition, some groups are developing minibrains for drug screening, to see if a given medication could be toxic to human patients' brains, according to a 2021 review in the journal Frontiers in Genetics.

Such models could complement or eventually replace research conducted with cells in lab dishes and in animals; even studies in primates, whose brains closely resemble humans', can't reliably capture exactly what happens in human disease. For now, though, experts agree that brain organoids are not advanced enough to partially or fully replace established cell and animal models of disease. But someday, scientists hope these models will lead to the development of new drugs and reduce the need for animal research; some researchers are even testing whether it could be feasible to repair the brain by "plugging" injuries with lab-grown human minibrains.

Related: FDA no longer requires animal testing for new drugs. Is that safe?

Beyond medicine and the study of human development, minibrains can also be used to study human evolution. Recently, scientists used brain organoids to study which genes allowed the human brain to grow so large, and others have used organoids to study how human brains differ from those of apes and Neanderthals.

Finally, some scientists want to use brain organoids to power computer systems. In an early test of this technology, one group recently crafted a minibrain out of human and mouse brain cells that successfully played "Pong" after being hooked up to a computer-controlled electrode array.

And in a recent proposal published in the journal Frontiers in Science, scientists announced their plans to grow large brain organoids, containing tens of thousands to millions of cells, and link them together to create complex networks that can serve as the basis for future biocomputers.

Could minibrains ever be sentient? 

Although sometimes called "minibrains," brain organoids aren't truly miniaturized human brains. Rather, they are roughly spherical balls of brain tissue that mimic some features of the full-size human brain. For example, cerebral organoids, which contain cell types found in the cerebral cortex, the wrinkled outer surface of the brain, contain several layers of tissue, as a real cortex would.

Similarly, brain organoids can generate chemical messages and brain waves similar to what's seen in a full-size brain, but that doesn't mean they can "think," experts say. That said, one sticking point in this discussion is the fact that neuroscientists don't have an agreed-upon definition of consciousness, nor do they have standardized ways to measure the phenomenon, Nature reported in 2020.

The National Academies of Sciences, Engineering, and Medicine assembled a committee to tackle these quandaries and released a report in 2021, outlining some of the potential ethical issues of working with brain organoids.

At the time, the authors concluded that "In the foreseeable future, it is extremely unlikely that [brain organoids] would possess capabilities that, given current understanding, would be recognized as awareness, consciousness, emotion, or the experience of pain. From a moral perspective, neural organoids do not differ at present from other in vitro human neural tissues or cultures. However, as scientists develop significantly more complex organoids, the possible need to make this distinction should be revisited regularly."

Editor's note: This article was updated on Jan. 8, 2024 to include new information about fetal tissue-derived minibrains. The story was originally published on Feb. 28, 2023.