On May 11, 2023, the U.S. Departments of Agriculture Animal and Plant Health Inspection Service announced it was taking emergency action to help protect the critically endangered California condors after several have died from highly pathogenic avian influenza (HPAI). APHIS has approved the emergency use of HPAI vaccine in an attempt to prevent additional deaths of these birds.

The authorized vaccine is a killed, inactivated product conditionally licensed by APHISﾒ Center for Veterinary Biologics in 2016. Since the vaccine has not previously been tested against this strain of the virus in these species, the first step in the vaccination program is a pilot safety study in North American vultures, a similar species, to investigate if there are any adverse effects before giving the vaccine to the endangered condors.