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.