As part of a new $1 billion plan to address bird flu in poultry and lower egg prices across the country, US secretary of agriculture Brooke Rollins announced Wednesday that the Department of Agriculture is considering vaccinating chickens against highly pathogenic avian influenza.
The US has dealt with flare-ups of bird flu in the past, but the current outbreak has been raging since 2022. The virus has been detected in wild birds in every state, which go on to expose commercial poultry and other animals. At least 166 million birds and 973 dairy herds have been affected in the current US outbreak. Infected animals have led to 70 cases of bird flu in people, including one death.
Bird flu is extremely deadly for poultry and can wipe out flocks quickly. To stop the virus from spreading, the USDA has long promoted culling infected birds. The practice has led to a 53 percent increase in egg prices from January 2024 to January of this year, and this week the USDA predicted an additional 40 percent increase in 2025.
In a Wall Street Journal editorial published Wednesday morning, Rollins said the USDA is “exploring the use of vaccines and therapeutics for laying chickens,” which should help reduce the need to depopulate flocks. She added that, “While vaccines aren’t a stand-alone solution, we will provide up to $100 million in research and development of vaccines and therapeutics, to improve their efficacy and efficiency.”
In addition to the $100 million the USDA is spending on vaccine research, the agency is committing $500 million for biosecurity measures on farms and $400 million in financial relief for affected farmers. It’s also exploring temporary import options and considering ways to increase the domestic supply of eggs.
Earlier this month, the USDA issued a conditional license to animal health company Zoetis for an updated bird flu vaccine for use in chickens. The conditional license was granted on the demonstration of safety, purity, and reasonable expectation of efficacy based on antibody responses in vaccinated chickens. Previous avian influenza outbreaks prompted the US to stockpile vaccines, but those shots are based on older strains of the virus and have never been used in poultry. One of those older vaccines, made by Zoetis and conditionally approved in 2016, was first used in 2023 by the US Fish and Wildlife Service to help protect California condors.
Chickens already receive several vaccinations for common diseases, and some countries are already vaccinating against bird flu, but the US has held out over concerns that immunization could hurt the exported poultry market.
“Many times vaccines are not completely effective against a viral challenge,” says Gino Lorenzoni, associate professor of poultry science and avian health at Penn State University. “The disease is probably not going to be fatal in many [vaccinated] animals, but the virus may still be reproducing and circulating within a population.”
The worry therefore is that if vaccination does not provide full protection, the virus could go undetected in poultry exports. Countries that buy poultry from the US could then impose trade restrictions because of the possibility of receiving infected products. When France decided to vaccinate ducks against bird flu in October 2023, the US and Canada banned certain French poultry imports. Those bans were partially lifted in January, after the French government was able to ensure safe trade.
In the US, poultry vaccination would likely focus on egg-laying chickens, as opposed to broiler chickens, which are raised for meat. During the current outbreak, more than 77 percent of the domestic poultry affected have been commercial egg-laying hens. In a USDA press release, Rollins said the agency is considering a “targeted and thoughtful strategy” for vaccination.
But the broiler chicken industry worries that even targeted vaccination of laying chickens would hurt the US, which is the second-largest exporter of poultry meat. Ashley Peterson, senior vice president of scientific and regulatory affairs at the National Chicken Council, says other countries are likely to ban all US poultry products, even if the US only vaccinates laying chickens. “When you move to a vaccine, you are essentially saying the virus is endemic and this is how we’re going to cope with it,” she says. “We would prefer to not cope with the virus. We would prefer to eliminate it completely.”
The organization supports the USDA’s current policy of culling infected flocks, as well as increasing biosecurity on farms—measures such as quarantining newly acquired animals, wearing protective clothing in poultry houses, disinfecting footwear before entering animal areas, and cleaning farm equipment.
But Carol Cardona, a professor of avian health at the University of Minnesota College of Veterinary Medicine, says biosecurity alone is unlikely to eliminate bird flu. “Farmers are so fatigued from hearing about biosecurity because they’re doing everything they can already,” she says. “Without more information about how those birds are getting infected, it’s very difficult to target biosecurity correctly.”
The virus can be carried in and out of poultry barns on shoes, clothes, and equipment that moves in and out of poultry barns. Mice, rats, and other small mammals can also carry the virus.
With the disease now so widespread, Cardona says, it will take more than one strategy to reduce outbreaks. “We’ve been fighting this fight with one hand tied behind our back, and I think there are other tools,” she says. “We have to create new methods to keep it out, and part of that is going to involve that vaccination.”
Even if vaccination doesn’t always prevent infection, Lorenzoni says it would still help reduce the amount of virus that’s circulating in the environment, which would slow down the spread of the disease to more farms.
And trade disruption could be brief. Rollins said the USDA will work with trading partners to limit impacts to export trade markets from potential vaccination. Lorenzoni says there will be pressure from other markets to keep the international exchange of poultry viable. “It is in everyone’s best interest to move as fast as they can with these commercial agreements,” he says.
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