Bird Flu Could Have Been Contained

Three years ago, when it was trickling into the United States, the bird-flu virus that recently killed a man in Louisiana was, to most Americans, an obscure and distant threat. Now it has spread through all 50 states, affecting more than 100 million birds, most of them domestic poultry; nearly 1,000 herds of dairy cattle have been confirmed to be harboring the virus too. At least 66 Americans, most of them working in close contact with cows, have fallen sick. A full-blown H5N1 pandemic is not guaranteed—the CDC judges the risk of one developing to be “moderate.” But this virus is fundamentally more difficult to manage than even a few months ago and is now poised to become a persistent danger to people.

That didn’t have to be the reality for the United States. “The experiment of whether H5 can ever be successful in human populations is happening before our eyes,” Seema Lakdawala, a flu virologist at Emory University, told me. “And we are doing nothing to stop it.” The story of bird flu in this country could have been shorter. It could have involved far fewer cows. The U.S. has just chosen not to write it that way.

[Read: America’s infectious-disease barometer is off]

The USDA and the CDC have doggedly defended their response to H5N1, arguing that their interventions have been appropriately aggressive and timely. And governments, of course, don’t have complete control over outbreaks. But compared at least with the infectious threat most prominent in very recent memory, H5N1 should have been a manageable foe, experts outside of federal agencies told me. When SARS-CoV-2, the virus that sparked the coronavirus pandemic, first spilled into humans, almost nothing stood in its way. It was a brand-new pathogen, entering a population with no preexisting immunity, public awareness, tests, antivirals, or vaccines to fight it.

H5N1, meanwhile, is a flu virus that scientists have been studying since the 1990s, when it was first detected in Chinese fowl. It has spent decades triggering sporadic outbreaks in people. Researchers have tracked its movements in the wild and studied it in the lab; governments have stockpiled vaccines against it and have effective antivirals ready. And although this virus has proved itself capable of infiltrating us, and has continued to evolve, “this virus is still very much a bird virus,” Richard Webby, the director of the World Health Organization Collaborating Centre for Studies on the Ecology of Influenza in Animals and Birds, told me. It does not yet seem capable of moving efficiently between people, and may never develop the ability to. Most human cases in the United States have been linked to a clear animal source, and have not turned severe.

The U.S., in other words, might have routed the virus early on. Instead, agencies tasked with responding to outbreaks and upholding animal and human health held back on mitigation tactics—testing, surveillance, protective equipment, quarantines of potentially infected animals—from the very start. “We are underutilizing the tools available to us,” Carol Cardona, an avian-influenza expert at the University of Minnesota, told me. As the virus ripped through wild-animal populations, devastated the nation’s poultry, spilled into livestock, started infecting farmworkers, and accumulated mutations that signaled better adaptation to mammals, the country largely sat back and watched.

When I asked experts if the outbreak had a clear inflection point—a moment at which it was crucial for U.S. leaders to more concertedly intervene—nearly all of them pointed to the late winter or early spring of last year, when farmers and researchers first confirmed that H5N1 had breached the country’s cattle, in the Texas panhandle. This marked a tipping point. The jump into cattle, most likely from wild birds, is thought to have happened only once. It may have been impossible to prevent. But once a pathogen is in domestic animals, Lakdawala told me, “we as humans have a lot of control.” Officials could have immediately halted cow transport, and organized a careful and concerted cull of infected herds. Perhaps the virus “would never have spread past Texas” and neighboring regions, Lakdawala told me. Dozens of humans might not have been infected.

[Read: America’s bird-flu luck has officially run out]

Those sorts of interventions would have at least bought more of the nation time to provision farmworkers with information and protection, and perhaps develop a plan to strategically deploy vaccines. Government officials could also have purchased animals from the private sector to study how the virus was spreading, Cardona told me. “We could have figured it out,” she said. “By April, by May, we would have known how to control it.” This sliver of opportunity was narrow but clear, Sam Scarpino, an infectious-disease modeler and flu researcher at Northeastern University, whose team has been closely tracking a timeline of the American outbreak, told me. In hindsight, “realistically, that was probably our window,” he said. “We were just too slow.”

The virus, by contrast, picked up speed. By April, a human case had been identified in Texas; by the end of June, H5N1 had infected herds in at least a dozen states and more than 100 dairy farms. Now, less than 10 months after the USDA first announced the dairy outbreak, the number of herds affected is verging on 1,000—and those are just the ones that officials know about.

The USDA has repeatedly disputed that its response has been inadequate, pointing out to The Atlantic and other publications that it quickly initiated studies this past spring to monitor the virus’s movements through dairy herds. “It is patently false, and a significant discredit to the many scientists involved in this work, to say that USDA was slow to respond,” Eric Deeble, the USDA’s deputy undersecretary for marketing and regulatory programs, wrote in an email.

And the agency’s task was not an easy one: Cows had never been a known source of H5N1, and dairy farmers had never had to manage a disease like this. The best mitigation tactics were also commercially formidable. The most efficient ways to milk cows invariably send a plume of milk droplets into the air—and sanitizing equipment is cumbersome. Plus, “the dairy industry has been built around movement” of herds, a surefire way to move infections around too, Cardona told me. The dairy-worker population also includes many undocumented workers who have little incentive to disclose their infections, especially to government officials, or heed their advice. At the start of the outbreak, especially, “there was a dearth of trust,” Nirav Shah, the principal deputy director of the CDC, told me. “You don’t cure that overnight.” Even as, from the CDC’s perspective, that situation has improved, such attitudes have continued to impede efforts to deploy protective equipment on farms and catch infections, Shah acknowledged.

Last month, the USDA did announce a new plan to combat H5N1, which requires farms nationwide to comply with requests for milk testing. But Lakdawala and others still criticized the strategy as too little, too late. Although the USDA has called for farms with infected herds to enhance biosecurity, implementation is left up to the states. And even now, testing of individual cows is largely left up to the discretion of farmers. That leaves too few animals tested, Lakdawala said, and cloaks the virus’s true reach.

The USDA’s plan also aims to eliminate the virus from the nation’s dairy herds—a tall order, when no one knows exactly how many cattle have been affected or even how, exactly, the virus is moving among its hosts. “How do you get rid of something like this that’s now so widespread?” Webby told me. Eliminating the virus from cattle may no longer actually be an option. The virus also shows no signs of exiting bird populations—which have historically been responsible for the more severe cases of avian flu that have been detected among humans, including the lethal Louisiana case. With birds and cows both harboring the pathogen, “we’re really fighting a two-fronted battle,” Cardona told me.

Most of the experts I spoke with also expressed frustration that the CDC is still not offering farmworkers bird-flu-specific vaccines. When I asked Shah about this policy, he defended his agency’s focus on protective gear and antivirals, noting that worker safety remains “top of mind.” In the absence of consistently severe disease and evidence of person-to-person transmission, he told me, “it’s far from clear that vaccines are the right tool for the job.”

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With flu season well under way, getting farmworkers any flu vaccine is one of the most essential measures the country has to limit H5N1’s threat. The spread of seasonal flu will only complicate health officials’ ability to detect new H5N1 infections. And each time bird flu infects a person who’s already harboring a seasonal flu, the viruses will have the opportunity to swap genetic material, potentially speeding H5N1’s adaptation to us. Aubree Gordon, a flu epidemiologist at the University of Michigan, told me that’s her biggest worry now. Already, Lakdawala worries that some human-to-human transmission may be happening; the United States just hasn’t implemented the infrastructure to know. If and when testing finally confirms it, she told me, “I’m not going to be surprised.”