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Bird Flu Accelerates Across America

For a more recent update on this topic, see here.


What began as a drop in milk production in Texan dairy herds has become an epidemic affecting humans, cats, alpacas, and other species across the United States. The culprit is a lethal bird flu virus called H5N1. Like other flu viruses, H5N1 is highly versatile and frequently moves from species to species, giving it pandemic potential. Since our last article on the virus, cases in both animals and humans have increased and the epicenter of infection appears to have shifted from Texas to Michigan.



So far, due to limited testing and delayed reporting, the reported numbers in this outbreak–69 infected dairy herds in 9 states, as well as a plethora of infections in other animals–appear to be a significant undercount. As of mid-April, milk from 15 states had already tested positive for the virus. Alarmingly, 5 of those states detected H5N1 in more than 75% of milk samples tested, including South Carolina and Arkansas, where no cow outbreaks had been confirmed. Even in California, where neither cows nor milk have tested positive, wastewater tracking has detected an early summer flu surge–unlikely to be from seasonal flu–indicating undetected circulation of H5N1.


H5N1 has been detected in milk across the United States. Source


Fortunately, the threat to the food supply appears to be moderate. Though the economic cost can be devastating for farmers, few cows have died from the virus. As for consumers, pasteurization kills the virus in infected milk and cooking does the same for contaminated meat, mitigating the risk of infection. However, the risk is not zero, partially due to the popularity of raw milk in the United States. Amidst the current outbreak, demand for raw milk has surged by 65% instead of decreasing as one might expect. Though not completely unexpected given the COVID-driven gap between health officials and the public, it's still bizarre to watch Americans defy government warnings in favor of TikTok influencers who claim that raw milk protects against H5N1.


A Fractured Response


The US government itself is not without fault in the current outbreak. The US Department of Agriculture already took significant criticism over its uploading of data and genetic sequences, which was limited and delayed. The information that was reported was often delayed and missed crucial details, such as the date and source of genetic sequences.


Meanwhile, in a disturbing parallel with the early days of the COVID-19 pandemic, testing has been abysmal, forcing scientists and health officials to fight the outbreak half-blind. Up until mid-April, only cows with symptoms were allowed to be tested for H5N1, just like how COVID testing was initially limited to travelers from China. Among humans, testing has also been severely limited. While the fact that only three people have tested positive for H5N1 so far may seem reassuring, less than two dozen were tested in total as of early May. Of course, one could argue that limited testing of humans and animals is not the government’s fault because farmers are refusing assistance. However, even wastewater testing, which has already been used the track the spread of the virus in ways traditional testing cannot, has been clumsy. One scientist complained that he needed “a drink" after the CDC advised against using an H5N1 test that he already had.



In another parallel with COVID, a tense election cycle is approaching, once again inhibiting collaboration between key government and private stakeholders, all while a new disease leapfrogs state borders and political battle lines. Already, conflict between federal agencies, state governments, and the agricultural sector has fractured control efforts. In one instance, Sid Miller, Commissioner of the Texas Department of Agriculture and one of presidential candidate Trump’s top options for USDA head, called federal efforts “overreach.” If there is already a breakdown between the federal government and a state at the heart of the outbreak, how much better could an actual pandemic response be?


On the bright side, there have still been no instances of H5N1 spreading from person to person in the United States, meaning that the current variant of the virus cannot cause a pandemic. Of course, only a handful of mutations that can occur almost overnight could completely change that.


The Vaccine Issue


Should H5N1 spill over and become a full-blown pandemic, we already have small vaccine stockpiles for other strains of the virus that may be effective. Assuming that the virus does not mutate to evade these vaccines, this would put us ahead of the curve compared to COVID, when the first batch of vaccine was not produced until over a month into the outbreak.


Manufacturing H5N1 vaccines could prove significantly more difficult than the standard flu shot production. Source: BRIAN SNYDER/REUTERS


The problem is production: because H5N1 is a new virus unfamiliar to human immune systems, people would need at least two doses. Furthermore, vaccinating half the population, as we do with seasonal flu, would be insufficient. This means that the US alone would need over 600 million doses and the world over 16 billion. As if that wasn’t enough, a study found that H5N1 vaccines would probably need 12 times the dosage used in typical flu shots to prompt an immune response, and effectiveness may be less than 50%. The best solution in this case would be adding adjuvants that stimulate the immune system, but even that would still make production more complicated compared to seasonal flu shot production.


Unfortunately, even with modern technology and lessons learned from COVID, the future impact of H5N1 remains largely up to luck–unless the US response is stepped up now.

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