USDA starts highly pathogenic avian influenza vaccine trials

The U.S. Department of Agriculture (USDA) is testing the efficacy of a handful of vaccines against the current strain of highly pathogenic avian influenza (HPAI) hoping to stem the spread of the largest outbreak of bird flu in the nation’s history. The virus has so far been reported in all but one state, Hawaii, and has resulted in the deaths of nearly 60 million poultry. While four vaccines are licensed for avian influenza—HA subtype, H5N1, H5N3, and H5N9—none are approved for the more virulent strain, H5N1 clade 2.3.4.4b, found in the current outbreak. This strain likely originated in wild birds, subsequently reached commercial poultry operations, then spilled over into nonhuman mammals, including mountain lions, coyotes, and bottlenose dolphins, which many have ingested infected birds. Read more