May 29, 2025 – The Department of Health and Human Services (HHS) has terminated funding for a major trial testing the safety and efficacy of a vaccine to protect Americans from bird flu, should the virus begin circulating in humans.
Moderna announced yesterday that it had achieved promising results in the first stage of its trials and was expecting to advance to “late-stage development” of the vaccines, when the HHS notified the drug company that the funding had been canceled.
The current outbreak of avian influenza began in early 2022 and has since affected more than 1,700 flocks—or a total of 173 million chickens and turkeys—in all 50 states. It began circulating in dairy cattle in 2024 and has infected more than 1,000 herds in 17 states. Seventy human cases have occurred so far, most of them in farmworkers in contact with livestock. Most of those have involved mild symptoms, with one death in an individual who had underlying health issues.
Recently, there have been some signs that the outbreak is abating. In California, where the largest number of human cases were reported, health officials announced they believe the worst is over. Most important, to date there is no evidence of the virus passing between humans, which would need to happen to spark a pandemic. However, experts say the virus is constantly mutating and it could happen at any time, with opinions varying on how likely that is.
The government already has three licensed, stockpiled vaccines for bird flu, but they don’t match current strains of the virus. That’s why the HHS, under President Biden, awarded Moderna more than $600 million to specifically “accelerate development of an H5N1 mRNA influenza vaccine that is well matched to strains currently circulating in cows and birds.”
But current Health Secretary Robert F. Kennedy Jr. is skeptical of mRNA technology, used to develop most COVID-19 vaccines. In an email to Civil Eats, HHS Communications Director Andrew Nixon said the agency’s decision reflects broader concerns about the use of mRNA platforms and referred to “mounting evidence” of side effects associated with COVID-19 mRNA vaccines, such as heart issues in young men.
“After a rigorous review, we concluded that continued investment in Moderna’s H5N1 mRNA vaccine was not scientifically or ethically justifiable,” he said in an emailed statement. “This is not simply about efficacy—it’s about safety, integrity, and trust. The reality is that mRNA technology remains under-tested, and we are not going to spend taxpayer dollars repeating the mistakes of the last administration, which concealed legitimate safety concerns from the public.”
While the COVID-19 vaccines were rolled out quickly, researchers had been developing mRNA technology for vaccines for about 20 years prior. The vaccines are associated with a significant increase in risk of myocarditis (inflammation of the heart muscle), especially in young men, but it’s such a rare condition that the actual occurrence is still extremely rare. Research also shows COVID-19 itself is more likely to cause the same condition.
In the meantime, Moderna said it “will explore alternatives for late-stage development and manufacturing” of the vaccines.
At the U.S. Department of Agriculture (USDA) in February, Secretary Brooke Rollins released a five-point strategy to address bird flu on farms, much of which was focused on bringing down egg prices and compensating farmers for dead birds. In March, she said more than 130 facilities had completed “biosecurity assessments” through the USDA and that funding was being made available to develop a chicken vaccine. However, in other statements, she walked back language on vaccinating livestock, which is a controversial trade practice. (Link to this post.)
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