Policy Backgrounders

Bird Flu: A New Strategy to Mitigate the Spread of H5N1

February 20, 2025

This Backgrounder updates CED’s Policy Backgrounder: Monitoring Possible Public Health Threats: Bird Flu: H5N1 Spreads to Pigs, which discussed public health concerns from the transmission of H5N1 to pigs; swine are viral “mixing vessels,” capable of being infected with both bird flu and human flu viruses. In recent days, the Administration has signaled a shift in the national response to bird flu from the mass culling of infected flocks to an approach centered on biosecurity and medication.

• A dozen large grade A eggs cost a record-high average of $4.95 in January 2025, up from $2.52 in January last year. A total of 159,307,978 poultry have been affected since the beginning of the outbreak.
• A recent CDC publication revealed that viral spillovers from dairy cattle into humans have gone undetected, including in states where dairy herds have not tested positive. The finding underscores the difficulty of detecting subclinical human infections.
• The Administration last week issued a conditional license for an avian flu vaccine from manufacturer Zoetis for use in chickens.
• A new H5N1 strain recently detected in Nevada dairy cattle showed a key mutation that may make it easier to replicate inside mammalian cells. However, there remains no evidence that H5N1 virus can spread human-to-human.
• USDA will soon release an official plan on bird flu; it is unclear whether the agency will adopt a strategy of stricter viral surveillance and testing measures.