When H5N1 avian influenza started spreading among dairy cattle across the U.S. this year, regulators warned against consuming unpasteurized milk. What happened? Raw milk sales went up.
Distributors of this unsafe-for-human-consumption product deny H5N1—which has the potential to sicken millions of people—is a danger. Dairy farmers decline to allow disease detectives onto their properties.
After 25 years of watching, waiting and worrying about bird flu, what finally tips it over into a pandemic could be American contrariness.
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Trust in public health and government are near an all-time low. At the same time, the federal government is unprepared for a new pandemic: It doesn’t have enough vaccines, and there is no plan for getting them out quickly. The public health infrastructure has not come even close to recovering after COVID, and people are going to resist measures that might help control a new epidemic, such as school closures or even mask use. The population is largely resigned to infection and death.
At such a vulnerable point in time, an old enemy, bird flu, moves into a new host: the milk cow. It’s an animal that people are in constant and intimate contact with, and whose flesh and milk are consumed daily.
One possible scenario for spillover into the population: a raw-milk drinker or a farmworker gets infected with this strain of H5N1 that’s moving among cattle and also gets co-infected with a human-adapted strain of influenza. In such a situation viruses can swap genes in a process called reassortment. A major fear about H5N1 has always been that it might do this. H5N1 has shown it can easily move from one species to another, acquiring new genetic material in the process.
Or someone catches H5N1 from a cow or its raw milk, and—perhaps through an immune deficiency—they develop a long-lasting infection that allows the virus to mutate in their body. “There absolutely is a risk here,” says Richard Webby, an expert in animal and human viruses who works at St. Jude Children’s Research Hospital in Memphis.
Here’s what it takes for a virus to start a human pandemic: it must acquire the ability to infect people easily; it must then pass easily from person to person; and it must cause significant illness.
“The more it spreads within mammals, that gives it more chances to mutate. As it mutates, as it changes, there is a greater chance it can infect humans. If it gains the ability to spread efficiently from person to person, then it would be hard to stop,” says Nita Madhav, a former U.S. Centers for Disease Control and Prevention researcher who is now senior director of epidemiology and modeling at Ginkgo Biosecurity.
This can happen fast. “We’ve all seen how a virus can spread around the globe before public health has even had a chance to get its shoes on,” Nirav Shah, principal deputy director at the CDC, said at a Council on Foreign Relations briefing in May. It only took three years for COVID to kill seven million people.
So far, the H5N1 virus has infected three dairy farm workers, according to the CDC. Those are the known cases. The CDC has not even begun to jump through the hoops needed to force inspections and testing—and any such moves would almost certainly result in prolonged legal battles with both the dairy industry and some states.
The symptoms were mild in two workers: an eye infection known as conjunctivitis. But the third worker had respiratory symptoms, the Michigan health department says – something that might lead to easier spread. The same strain of the virus has killed more than a few farm cats, and a study published in the New England Journal of Medicine in May shows the virus infected multiple organs in mice that drank H5N1-contaminated raw milk. Mild symptoms mean it could be spreading, unnoticed, among people.
What’s called for now is stepped-up surveillance, ideally on dairy farms across the country, with regular testing of the milk supply and in clinics where dairy farms are concentrated. Ideally the CDC would test populations of raw milk enthusiasts. The CDC and the U.S. Department of Agriculture are trying to get onto farms to test, but with only limited success. Dairy owners don’t want the stigma of having the virus found on their farms, and workers are worried they will be questioned about their immigration status or that they’ll be deported if they are found to be infected.
Worse, if the federal government does decide to take a serious stand on the virus and announce measures to get out ahead of it, it will almost certainly become a divisive campaign issue in the current election. It is easy to imagine former president Donald Trump telling his supporters that the Biden administration is inventing an imaginary threat to scare them.
Moreover, disinformation and misinformation have never been worse, thanks in no small part to social media. “Drink raw milk so that you don’t get bird flu,” urges one distributor on X, formerly Twitter. People have always had odd ideas about how to resist disease, from the notion that eating certain diets can boost immunity to the widely debunked Great Barrington Declaration that called for allowing COVID-19 to spread through most of the population to build up some kind of natural immunity, a recipe for overloaded ICUs and mass deaths.
These are all natural reactions, says Jennifer Nuzzo, professor of epidemiology and director of the Pandemic Center at Brown University School of Public Health: “When extraordinary things happen, a common psychological response is to deny it. ‘It can’t be happening.’”
But after having seen this response in real time during COVID, the U.S. and many other governments have done too little to learn from their mistakes. “We have literally not made any serious effort to understand what worked and what didn’t,” Nuzzo says.
The federal government and its agencies haven’t even gone back to pre-COVID studies about how to communicate with the public and how to coax the reluctant into cooperating with public health measures. It takes a gentle, almost personalized, approach—one that would work best on the basis of a long-term, familiar relationship. The best messengers are individuals or institutions that already have the trust of the targeted audience.
“In an ideal world our response to [a pandemic threat] would be voluntary where everyone chooses to take actions to protect themselves, their community, their loved ones,” Nuzzo says. “We just can’t compel people to take action that is not in their best interests. You have to convince them that it is in their best interests and help people feel like they are part of the solution.”
But in 2024 trust in institutions is elusive. The FDA urged consumers to avoid raw milk after H5N1 was found in one out of five samples of commercially available milk it tested. That’s when sales of raw milk took off.
“People that follow us—if FDA says it’s bad, they'll run [toward] it,” Marc McAfee, a dairy farmer in California who founded the Raw Milk Institute, told NPR. That’s what raw milk promoters are doing now.
There’s never a good time for a flu virus to find a new way to circulate, but with American stubbornness hitting a new peak, 2024 could not be a worse time.
This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.
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