Federal health agencies oppose the use of bird flu vaccines in poultry right now, Health and Human Services Secretary Robert F. Kennedy Jr. said, weighing in publicly on it for the first time in his new role. The Trump administration has been considering poultry vaccination as it seeks to combat the outbreak that is fueling a record surge in egg prices.
U.S. Department of Agriculture officials said last month that they were ramping up planning on potentially deploying a vaccine for poultry, with the hopes of putting a draft of the plan before trading partners “as quickly as possible,” since it could affect billions of dollars in exports.
“There’s no indication that those vaccines actually provide sterilizing immunity and all three of my health agencies, NIH, CDC, and FDA, the acting heads of those agencies have all recommended against the use of the bird flu vaccine,” Kennedy said in an interview on Fox News published this week.
Sterilizing immunity means vaccine protection that completely stops infections and spread. Vaccines are rarely able to offer this kind of effectiveness, though the USDA said last month it would step up investments in “potential new generation vaccines” with better protection.
Kennedy’s remarks mark a sharp turn from the Biden administration, multiple former officials said.
Biden officials from the health and agriculture departments had wrestled extensively with calls to roll out vaccines for animals as outbreaks mounted on farms nationwide. It was concerns from agriculture officials, not human health officials, that ultimately blocked plans to roll out vaccines.
“At no point did they express a concern or anything other than robust support for an animal vaccination program,” one former USDA official said of the health agencies.
At the time, Biden-era health officials viewed the ultimate decision as one outside of their expertise and better left to agriculture department experts, two people familiar with the planning said.
Would vaccinating poultry turn birds into “mutant factories”?
Kennedy said the new opposition from his health agencies was based on concerns that vaccinating poultry without being able to provide sterilizing immunity would amount to “turning those birds into mutant factories,” resulting in worrying genetic changes to the virus.
“That could actually accelerate the jump to human beings,” Kennedy said.
Experts say vaccination would need to be managed with strict biosecurity measures — extra precautions to prevent vaccinated birds from becoming infected — to reduce the risk of genetic changes in the virus.
“Creating conditions where the virus can freely mutate increases the likelihood of a strain emerging that can infect humans,” said Daniel Perez, chair in poultry medicine at the University of Georgia, in an email.
Perez said the risk is higher in large-scale poultry operations, where birds can have weaker immune systems.
But he added that he sees vaccination as a strategic option to curb outbreaks for egg-laying chickens and backyard poultry, alongside other measures like intensive surveillance to detect outbreaks and continued culling of infected flocks of chickens raised for meat.
“Vaccination can be a useful tool when combined with strict biosecurity. If birds are kept from exposure to the virus, then vaccination can help to contain outbreaks,” said Perez.
Instead, Perez warned that another idea floated by Trump administration officials could pose a far greater risk: relying on immunity from poultry surviving bird flu infections.
“We’ve in fact said, at the USDA, that they should consider maybe the possibility of letting it run through the flock so that we can identify the birds and preserve the birds that are immune to it,” Kennedy had said.
Perez said this approach would make surviving birds breeding grounds for worrying mutations.
“This implies a potentially dangerous misunderstanding of how avian influenza works. Allowing highly pathogenic avian influenza to spread through a poultry flock is extremely risky and counterproductive,” he said.
The Biden administration opted against vaccinating poultry for different reasons, former officials said.
Agriculture officials had worried it could lead to missed spread of the virus through asymptomatic birds, trigger bans on imports of U.S. poultry products and be logistically challenging to thoroughly administer to massive commercial flocks.
Kennedy’s comments come days after the Centers for Disease Control and Prevention released an updated assessment of the virus, finding that the risk remains “low” to the general population but higher for people like farm workers or veterinarians who might be exposed to infected animals or contaminated surfaces.
Most confirmed bird flu cases in humans to date have been largely mild, except for a handful of hospitalizations and one death.
The CDC stressed that its assessment of the risk, while low at this time, “could change, as influenza A viruses can mutate quickly, and therefore have the potential to cause pandemics.”
