Avian flu (H5N1) was considered a potential risk for a pandemic in 2019, the same year that COVID-19 burst on the scene in China and swiftly swept throughout the world, killing many millions and leaving in its wake 10 percent of the cases with an enigmatic chronic debilitating disorder called long COVID.
The toll of COVID would have been far worse without the willing acceptance by most of the public of the importance of social distancing and masking, which stemmed the spread of virus between late 2019 and early 2021 when effective vaccines became widely available and further reduced transmission of the virus and the need for COVID-related hospitalizations.
By the two-year mark, public support for social distancing and masking in public spaces and vaccines began to wane, fuelled by growing internet-fed misinformation about the need for public health restrictions, especially masking, and false claims that the vaccines were not only ineffective but associated with risky side effects.
The result was increasingly politized opposition to public health measures and vaccination programs in the face of the emergence of new variants.
For the majority, COVID has become a ho-hum affair and updated vaccines of little interest, except for the old or other higher-risk groups. But for the rest, most treat COVID as no more of a risk than the common cold and no reason to restrict their social activities.
That might change with the emergence of H5N1 as a potential threat to humans.
These days the attention of some public health experts has shifted. To quote Kai Kupferschmidt writing in Science (Dec. 13, 2024), “If the world finds itself in a flu pandemic in a few months, it won’t be a big surprise. Birds have been spreading a clade of the H5N1 avian influenza virus, 2.3.4.4b around the world since 2021.”
That tone is reflected in the views of many virologists and infectious disease experts who were alarmed at the spillover of H5N1 to cattle in the United States last year and subsequent spread to hundreds of farms.
There were earlier encounters with avian flu such as the 1997 H5N1 outbreak, which killed 6 of 18 infected humans who had been in contact with infected poultry. But so far, fortunately, there has been no evidence of direct human-to-human transmission.
But some experts believe it’s only a matter of time before mutant versions of the H5N1 virus target humans, especially the respiratory tract, while at the same time evading the body’s immune system, much as COVID did.
The virus’s genome has been mapped many times. Three mutation targets stand out.
One, a polymerase enzyme, is responsible for replicating the virus, mutant versions of which might be more effective at cranking out viral copies.
A second target for mutation could be hemagglutin, which might make the virus more infectious.
The third plausible target is neuraminidase, which helps new viral buds detach from infected cells — thus spreading the infection more efficiently.
Those are the three mutant possibilities we know about, but there could be other targets we don’t know about for H5N1 that could make human-to-human transmission more likely and others that might adversely affect human immunological responses to the virus.
The point is that H5N1 has moved much closer to humans through transmission to animals with which humans are in contact on a regular basis — and might mutate to make animal-to-human transmission much easier and prompt the risk of further mutations, which could make human-to-human transmission as easy as was the case with COVID.
That would put us at risk for a second pandemic in less than a decade, and this time, the political climate has changed and might hobble our response to a possible pandemic.
For one, the new administration in the U.S. is skeptical of public health measures and vaccines in general. With COVID, at least the major players were on the same team in the urgency with which they responded in Donald Trump’s first term.
Now, the National Institute of Health, which was a key player in the response to COVID, may be subject to defunding and unsettling reorganization. Making matters worse is the growing skepticism about science in general and vaccines among the public.
Corralling worldwide pandemics require cooperation and collaboration with other governments and health care agencies. Without that, it’s hard to see how keeping up with changes in viruses will be possible, especially if the responsible agencies are underfunded and unsupported. None of that was in doubt with COVID but is now.
It’s not just a matter of COVID or H5N1 — it’s any virus that potentially could threaten humans.
Risks increase with rising numbers of humans in close contact with birds and other vectors in which reservoirs of viruses have many more opportunities to mutate their way to making the jump to humans easier and possibly opening the door to direct human-to-human transmission and even the emergence of lethal variants.
Finally, in this era of gene editing, it’s easy to create more lethal, spreadable infectious agents in the lab with little investment. Imagine those tools in the hands of ISIS or other renegade parties.
Dr. William Brown is a professor of neurology at McMaster University and co-founder of the InfoHealth series at the Niagara-on-the-Lake Public Library.