Year in review: The standout health stories of 2025, from measles outbreaks to AI-made viruses

Groundbreaking medical treatments; mysteries of fundamental biology; the impacts of health policy upheavals. Live Science covered all these topics and more in 2025 — and you can catch up on some of our best Health channel long-reads from the year below. The following list includes interviews, book excerpts and news analyses, as well as entries from our Science Spotlight series, which highlights how science is transforming the world as we know it.

1. Secrets of the world's oldest woman

Maria Branyas Morera, once the world's oldest woman, died in 2024 at age 117. Live Science took a deep look at a study that examined Branyas' biology and uncovered key traits that may have protected her from disease in old age. Could lessons from the study help others lead longer, healthier lives?

2. What makes us human?

Many consider the brain to be a central feature of what makes us human — but how did the remarkable organ come to be? In an interview, science communicator Jim Al-Khalili discussed what he learned from shooting the new BBC show "Horizon: Secrets of the Brain," which tells the story of how the human brain evolved. And in a book excerpt and interview with Live Science, neuroscientist Nikolay Kukushkin described the evolutionary forces he believes were key to the formation of the human brain and consciousness as we know it.

3. Could lab-grown brains gain consciousness?

Miniature models of the human brain can be grown from stem cells in the lab, and they're getting more and more advanced. Some scientists have raised concerns that these "minibrains" could become conscious and feel pain. We investigated experts' concerns and hopes for future regulation of the research.

4. The promise of mRNA medicine

mRNA may be best known for forming the basis of the first COVID-19 vaccines, but it could also be used in revolutionary cancer therapeutics, immune-reprogramming treatments and gene therapies. The promise of these emerging mRNA medicines is staggering, but due to the politicization of COVID-19 shots in the U.S., mRNA research and development — even unrelated to vaccines — now hangs in precarious uncertainty. A Science Spotlight feature described emerging mRNA technologies and their wobbly status under the second Trump administration.

5. Cancer in young people

You may have heard that more young people are being diagnosed with cancer. But which types of cancer are driving this trend? And why are the rates going up in the first place? We looked at what may be driving this pattern, from underlying cancer triggers to better techniques for early detection.

6. Male vs female brains

Is there really a difference between male and female brains? And do we even have the data required to answer that question? A Science Spotlight explored the existing research on sex differences in the brain, finding the results murkier than one might expect. Headlines often proclaim that male and female brains are "wired differently," and that may be true in some subtle ways. But the biological consequences of those differences remain unclear, even to experts in the field.

7. AI is designing viruses

Artificial intelligence can now be used to design brand-new viruses. Scientists hope to use these viruses for good — for example, to treat drug-resistant bacterial infections. But could the technology usher in the next generation of bioweapons? An analysis probed this dual-use problem and what can be done to safeguard our biosecurity.

8. When pandemics are a "certainty," how do we prepare?

In a book excerpt, epidemiologist Dr. Seth Berkley explained how he and other health leaders orchestrated a massive vaccine rollout to poor countries during the COVID-19 pandemic, so that the shots wouldn't exclusively be hoarded by wealthy nations. Live Science also spoke with Berkley about the lessons learned from the pandemic and the ongoing fight for vaccine equity.

9. USAID cuts

The United States Agency for International Development (USAID), once the world's largest foreign aid agency, was hit by massive funding cuts under the second Trump administration. A few of its functions will reportedly continue, under the control of the Department of State. We looked at the predicted and devastating effects that the loss of USAID will likely have on HIV care worldwide. And in an interview with author John Green, who published a book on tuberculosis (TB) this year, we explored what the cuts could mean for TB patients.

10. Microplastics on the brain

A study went viral after suggesting that healthy human brains may contain a similar amount of plastic as the average plastic spoon. But should we really be concerned? Our analysis broke down what we know and what we don't about microplastics in the brain.

11. Dodging early Alzheimer's disease

A man genetically guaranteed to develop early Alzheimer's disease is still disease-free in his 70s. We explored the details of the man's case, digging into his genetic profile and the broader lessons it could teach scientists about dementia.

12. Mental health after weight-loss surgery

Weight-loss surgeries often come with improvements in mental health — but research revealed that this effect is less tied to the weight loss itself and more connected to the relief from stigma that people often experience post-procedure. We examined this finding and what it can tell us about the profound impact of weight stigma on people's health and well-being.

13. Measles makes a comeback

In 2000, the United States hit a public health milestone by eliminating measles. But now, there's been a sustained resurgence of the highly infectious disease, putting the country on the brink of losing that precious elimination status. This story explained how we got here and what's at stake. And in an opinion piece, several experts called out the anti-vaccine movement that drove down measles vaccination rates — a movement that health secretary Robert F. Kennedy Jr. has been spearheading for years.

14. Is America losing the war on cancer?

In a book excerpt, Nafis Hasan argued that the United States has been employing the wrong strategies to fight cancer for decades. While hyperfocusing on finding treatments for individuals with cancer, America has largely ignored population-level strategies that could help drive down cancer rates and cancer deaths across the board, he argued.

15. Threats to fetal tissue research

The U.S. federal government is threatening to restrict research conducted with human fetal tissue. In an opinion piece, cell biologist, geneticist and neuroscientist Lawrence Goldstein dispelled widespread myths and misinformation about this type of research.

16. "The Big One," a disaster to dwarf COVID-19

Epidemiologist Michael Osterholm predicts that the next pandemic could be even worse than COVID-19. In a book excerpt and interview with Live Science, Osterholm described the lessons we should have taken away from the coronavirus pandemic, and how recent changes in U.S. policy may have destroyed our capacity to handle serious outbreaks.

17. Climate change may drive up hyponatremia

As the planet warms, a dangerous condition called hyponatremia may be on the rise. The condition causes a dramatic decline in sodium in the body, which can potentially cause seizures, coma and death. A Live Science exclusive looked at the emerging trend.

18. Baby-making robots?

A viral story suggested that researchers in China were working on a "pregnancy robot" that could gestate a human baby from conception to birth. It turns out that the story was complete fiction — but, in theory, could such a technology be realized? Experts weighed in on the sci-fi-sounding idea and discussed whether, eventually, it could be feasible to build a bona fide pregnancy robot.