bird flu, mpox, future of the WHO

Here we are, on the cusp of the midway point in a decade that has been, in global health and infectious diseases terms, a lot.

The 2020s started with the most severe pandemic since the 1918 Spanish flu. Just as the worst of Covid-19 was starting to ease, the world was introduced to mpox, a cousin of smallpox that went from occasionally infecting people who had contact with infected rodents in forested parts of West and Central Africa to spreading from person to person in Europe, the Americas, and beyond, mainly via sex. In 2024, bird flu became cow flu, or moo flu, as some researchers like to refer to it. Between outbreaks in dairy cows, outbreaks in poultry operations, and outbreaks in wild birds, the amount of H5N1 virus in the environment has reached unsettling levels.

So what does 2025 have in store for us on the global health front? Unfortunately, it doesn’t feel like the 2020s are ready to cut us any breaks. The list of things we at STAT are watching is long, but here are three that we’re pretty sure will be grabbing headlines in the new year.

What’s going to happen with H5N1 bird flu?

H5N1, a viral family that traces its lineage back to an influenza virus isolated in China’s Guangdong province in 1996, has often had the scientific world on edge over the ensuing three decades. After a period of relative quiet in the second half of the previous decade, it has roared back in the past couple of years, infecting an astonishing array of mammals. (Astonishing because this is, after all, a bird version of flu.) In 2024, the world discovered the virus was transmitting among dairy cows in the United States, a stark reminder that you should always expect the unexpected with H5N1.

Flu viruses that don’t circulate among people could trigger pandemics, if they acquire the capacity to easily infect us. There are two ways they can make that jump. The first is by mutation — the acquisition of random genetic changes that would let a virus currently suited to infecting birds become a virus that can easily infect people. Spending time infecting a mammalian species like cows could set H5N1 on that path.

The second is a process called reassortment. When different flu viruses co-infect a host — a duck, a pig, maybe a cow or a person — they can swap genes, giving rise to hybrids of the original viruses. With flu season settling in across the country, some farmworkers will contract seasonal flu, and some of them will go to work sick. If someone were to catch both seasonal flu and H5N1 at the same time, the former could give the latter some genes that could make H5N1 transmissible to and among people.

Will that happen? There’s no way to estimate the odds. If H5N1 does start a pandemic, would it be a deadly one? That’s another unanswerable question. But having this virus circulating in dairy cows is like allowing Mother Nature to keep throwing dice at a craps table. The house normally wins. But it doesn’t always.

In the time since H5N1 found its way into cows it has been making regular forays into people. By Dec. 23, the Centers for Disease Control and Prevention had confirmed 65 human infections in 10 states in 2024. And that’s only part of the story. There were plenty of anecdotal reports of dairy workers with similar symptoms who didn’t go for testing. Studies looking for missed cases by studying the blood of exposed people have found more people have been infected than have been confirmed as cases. With the exception of a case in Louisiana recorded earlier this month, all known cases in the U.S. have been mild.

From the start, the dairy industry has treated this outbreak as if it is merely a cow problem, one to be soldiered through. The U.S. Department of Agriculture hasn’t challenged that in any significant way, asserting without any discernible evidence that the virus will eventually burn itself out. Only recently has the department decided to actively go looking for the virus, with a mandatory bulk testing program that started only in six states but has since been expanded to seven more.

Whether the virus will burn itself out in cows is yet another of the unanswerable H5N1 questions. States that had infected herds early on — Kansas, for example — haven’t reported new infections for months. Is that because there are none? Or because farmers won’t test their cows? These questions have answers, but getting them requires political will that, in a presidential election year, has been absent.

An answer may come from California, the country’s largest dairy producer, where the virus has stormed through more than two-thirds of the state’s herds — 675 — since the first infections were detected at the end of August. California is actively looking, both for infections in cows and infections in people, and it is reporting its findings. Presumably if the virus starts to cycle through herds for a second or third time, that will be detected there.

Meanwhile, studies of the specific version of the virus currently circulating suggest there may be fewer hurdles standing in the way of this iteration of H5N1, known as clade 2.3.4.4b, acquiring the capacity to easily infect people than there were for earlier versions of the virus.

Is the stage being set for an H5N1 pandemic? We don’t know. But we’ll continue to watch this story closely.

Can the spread of mpox be stopped?

In the spring of 2022, health authorities in Britain startled the world when they announced they had detected local transmission of monkeypox, a disease caused by a member of the poxvirus family. Mpox, a virus that was initially transmitted through sexual contact, has evolved and spread rapidly around the world. Originally known as a disease affecting communities of gay, bisexual, and other men who have sex with men, the virus has now mutated into different clades, with some versions being spread through sex while others are transmitted through household contacts of infected individuals.

In 2022, cases of clade IIb mpox were prevalent in various countries, but behavioral changes and the deployment of vaccines designed to protect against smallpox helped slow down the spread of the virus. However, cases of clade IIb are still appearing in regions where mpox was previously non-existent. Additionally, in 2024, clades Ia and Ib emerged in African countries, leading to human-to-human transmission through sexual contact and household interactions.

Despite efforts to contain the spread of the virus, transmission of clade I viruses in Africa has been challenging to control. With nearly 14,000 laboratory-confirmed cases and 60 deaths reported in 20 African countries, the global impact of mpox is significant. The World Health Organization has reported almost 22,500 confirmed cases and 78 deaths from 82 countries worldwide in the same year.

The limited availability and high cost of the Jynneos vaccine, the primary vaccine against mpox, have hindered efforts to vaccinate at-risk populations globally. The cessation of smallpox vaccination campaigns in the past has left a growing population vulnerable to poxviruses, with the majority of confirmed cases occurring in individuals aged 18 to 49.

The WHO declared mpox a public health emergency of international concern in 2022 and again in 2023 as the spread of the virus persisted. Looking ahead to 2025, the question remains whether human-to-human transmission of mpox can be effectively contained or if it will become a permanent aspect of a world with declining immunity to poxviruses.

In parallel with the mpox crisis, the status of American influence in global health is also at risk. The potential withdrawal of the United States from the WHO, as hinted by the incoming administration, could have far-reaching consequences. The U.S. has been a significant contributor to the WHO both in terms of financial support and expertise, and its departure could jeopardize critical programs and initiatives within the agency.

The WHO has been striving to diversify its funding sources, but losing the U.S. as a member would pose a substantial setback. The absence of American contributions could lead to a shift in power dynamics within the organization, potentially allowing other major donors like China or the European Union to exert greater influence.

Ultimately, the combined challenges of the mpox pandemic and the potential decline of American influence in global health underscore the need for international cooperation and solidarity to address complex public health crises effectively. As the world navigates these interconnected issues, collaboration and support from all nations will be crucial in mitigating the impact of emerging infectious diseases and safeguarding global health security. With potential cuts to research efforts at the CDC and funding through the National Institutes of Health looming, scientists in the United States may be looking for new opportunities abroad. Isabella Eckerle, the director of Switzerland’s Geneva Centre for Emerging Viral Diseases, believes that European institutions could soon see an influx of top U.S. talent in the field of infectious disease research.

Eckerle predicts a “golden opportunity” for European institutions to recruit skilled researchers from the U.S. She anticipates a brain drain of academics from the U.S., which could significantly benefit European research efforts in infectious diseases. This influx of talent could drive innovation in tools, data science, drug development, and vaccine development, ultimately benefiting Europe for years to come.

The potential for a mass exodus of scientists from the U.S. to Europe could have far-reaching implications for the scientific community. As funding and resources become scarcer in the U.S., researchers may be forced to seek opportunities elsewhere in order to continue their work and make meaningful contributions to their fields.

As we look towards 2025, it is clear that the landscape of scientific research could undergo significant changes. With the possibility of major cuts to research funding in the U.S., scientists may need to explore new horizons in order to continue their work and advance their careers. The scientific community is bracing for what could be a turbulent period ahead, with potential opportunities for growth and collaboration on a global scale.