When asked in a recent Sermo poll whether they were concerned that bird flu could become the next pandemic, physicians were split: 60% said yes, 40% said no.
This division between doctors reflects the tension between what is known, that the majority of current human cases remain tied to animal exposure, with no evidence of sustained human-to-human spread and what cannot be predicted, the possibility that the virus could evolve into something far more dangerous.
That uncertainty feels more potent in 2024–2025, following a string of unusual outbreaks. In March 2024, the U.S. Centers for Disease Control and Prevention (CDC) confirmed the first detection of avian influenza A(H5N1) in cattle. Since then, more than 70 human cases have been reported in dairy and poultry workers across several states, with one confirmed United States death. The shift into cattle is without precedent in the United States and combined with the wide range of species now affected, from wild birds to cats, the risk is clearly changing.
As one intensive care physician on Sermo explained: “When avian influenza is transmitted to humans, symptoms in people can range from a mild upper respiratory tract infection (fever and cough) to severe pneumonia, acute respiratory distress syndrome (difficulty breathing), shock and even death.”
Given those stakes, it is no surprise that physicians are paying close attention. Drawing on Sermo community insights and recent CDC updates, here’s what doctors are worried about, what they expect to see next and why prediction remains one of the biggest challenges of all.
What’s happening with bird flu now?
The latest outbreaks in the United States began in Texas and Kansas in March 2024. This is when dairy cattle and a small number of farm cats tested positive for H5N1.
Soon after, human cases were confirmed, one of which was in a Texas farmworker whose main symptom was conjunctivitis, then there were later additional infections in poultry and dairy workers. This event was the first time in United States history that H5N1 was detected in cattle, which has since shifted the conversation from being considered “bird-only” to a wider threat encompassing many species.
According to the CDC’s most recent update (August 2025), the U.S. has now recorded:
- 70 confirmed or probable human cases since 2024.
- 1 death (reported in Louisiana).
- Most exposures tied to cattle (41 cases), followed by poultry farms (24 cases), with a handful linked to wild birds, backyard flocks or other animals.
- No evidence of person-to-person spread so far.
Globally, the CDC reports a further 26 human cases in 2025, many of which have been connected to poultry or wild bird exposures.
These outbreaks differ from earlier H5N1 events in 2005 and 2013, when the virus was mostly limited to poultry that would occasionally spill over into humans. What makes today’s situation more concerning is the breadth of affected species, which now includes cattle, cats and other mammals. This suggests the virus is expanding its host range.
Therefore, even if the risk to the general public remains officially “low,” most physicians watching these infectious diseases agree the situation demands close monitoring.
Pandemic potential: What are doctors worried about?
When we asked doctors on Sermo whether bird flu has the potential to evolve or mutate into a bigger threat, 77% said yes.
That’s not surprising given what we know about how the flu works. It tends to evolve in two main ways:
- Antigenic drift: those small, steady mutations that build up over time.
- Antigenic shift: the bigger shake-ups, when two flu viruses infect the same host and swap genetic material, creating a new hybrid strain.
It’s those sudden shifts that have triggered past pandemics. Think of the 1918 H1N1 pandemic (likely from a bird virus adapting to humans) or the 2009 H1N1 pandemic (which came out of swine). For doctors today, the concern is that bird flu spilling over into cattle or other mammals could set the stage for one of these dangerous reassortment events.
The other worry is straightforward: zoonotic spillover, the transmission of pathogens from wild animals to humans. Most United States human cases so far have been in dairy workers or poultry farm staff, people in close contact with animals every day. Each human infection gives the virus another opportunity to adapt for more efficient transmission.
Diagnostic gaps make the situation more challenging. Bird flu doesn’t always present like regular seasonal flu. Some patients only get eye redness (conjunctivitis), while others develop severe pneumonia and acute respiratory distress. The milder or more unusual cases may slip through the cracks, meaning official numbers might underestimate what’s really happening.
And this is where the poll results get really interesting: while 77% of doctors on Sermo believe mutation is a genuine risk, only 60% think bird flu could realistically become the next pandemic. In other words, most agree the risk is there, but they also know not every mutation leads to human-to-human spread. Hence, the danger is real, it’s just not inevitable.
What doctors expect next with the spread of H5N1
Sermo data shows 80% of physicians expect more human cases and 87% expect the outbreak to spread geographically. And this is because the conditions favor it:
Migratory birds
Wild birds are the natural carriers of H5N1. They move the virus across continents along their migration routes and past outbreaks have mirrored those routes almost exactly. With infected flocks now documented in Asia, Europe and the Americas, many doctors see wider spread as less a question of “if” and more a matter of “when.”
Industrial farming and livestock contact
High-density farming is the perfect environment for a virus to spread and the risk for those working with animals is obvious. Farmworkers, vets and anyone handling unpasteurised milk remain on the frontline to the risk of being exposed.
Animal-to-human contact beyond farms
Reports of infected cats in Texas and Kansas remind us how unpredictable this virus can be. Once pets and working animals are involved, the range of possible exposures grows.
Surveillance systems
In the United States, surveillance has been relatively strong: more than 204,000 specimens tested and over 18,600 people monitored after exposure, leading to the detection of 70 human cases. But that picture isn’t consistent everywhere. Surveillance is key to preparedness, and many doctors worry that in regions with fewer resources where spillover is most likely, early cases may go undetected until the virus has already spread beyond containment.
Vaccine R&D
There are candidate H5N1 vaccines in development and even stockpiles maintained by agencies like the Biomedical Advanced Research and Development Authority (BARDA). But, as physicians are well aware, vaccine readiness is never perfect. If a future pandemic strain doesn’t match the vaccines currently on hand, those efforts may buy time but not provide full protection.
Public health measures
CDC guidance stresses familiar steps under their new One Health policy, like wearing personal protective equipment and notifying the CDC of suspected cases within 24 hours. The concern many physicians raise is whether those measures would be rolled out quickly and decisively enough if the number of human cases began to climb.
Why predicting the next pandemic is so difficult
When asked whether predicting a bird flu pandemic is difficult because viral genetic exchange is essentially random, 92% of physicians on Sermo agreed. And with good reason. Pandemics don’t follow a neat pattern and instead come out of a mix of biology and chance.
Take genetics. For decades, pigs have been labelled the “mixing vessels” for this kind of event. Now, with confirmed H5N1 infections in U.S. cattle, physicians are asking whether other livestock could be playing a similar role. The uncomfortable truth is that no model can tell when or where reassortment will tip over into something pandemic-ready.
History backs this up. The 1918, 1957, 1968 and 2009 pandemics all came from sudden reassortment events. None were predicted in advance, and all changed global health practically overnight. That unpredictability is exactly what worries physicians now.
Then there’s the current uncertainty with H5N1 itself. The United States has seen 70 cases and one death, so it’s known that human infection is possible. But sustained person-to-person transmission has yet to be seen. The virus could remain an occasional zoonotic infection linked to farms and wild birds, or it could adapt further. Right now, both scenarios are plausible.
And finally, surveillance and modelling have limits. Surveillance picks up new strains only once they’re circulating, not before. Sequencing gives clues about mutations of interest, but it can’t tell which genetic changes will actually enable efficient human spread. That gap between what they can measure and what really matters is why so many doctors conclude: yes, pandemics are possible, but no, we can’t predict them.
Your takeaway
Physicians on Sermo are divided on whether bird flu could realistically become the next pandemic, with 60% expressing concern and 40% remaining unconvinced.
What unites most according to the Sermo data, however, is the belief that mutation poses the greatest threat, as 77% highlight the risk of viral evolution. The majority also anticipate further spread, with 80% expecting additional human cases and 87% predicting wider geographic reach. At the same time, 92% agree that pandemics are essentially impossible to predict, given the randomness of viral genetic exchange.
Against this backdrop of uncertainty, doctors consistently stress that preparedness is key, from strong surveillance to rapid public health responses.
Join the discussion on Sermo
How are you talking about bird flu with colleagues or patients? Are you seeing more concern in your clinic? Have you implemented any bird flu treatments?
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