Details from a FOIA request to the USDA have revealed severe adverse events following injection of the Nobivac NXT canine flu H3N2 vaccine, the first self-amplifying RNA (saRNA) vaccine widely used in the US for pets. The aftermarket reports received by The HighWire show the first 1,012 pages of 1,888 total pages of adverse events from September 2024 through July 2025. There were 296 cases involving the Nobivac RNA vaccine as a suspect product: 152 were adverse reactions, and 76 were listed as cases of lack of efficacy, meaning the dogs developed respiratory illness or cough after receiving the vaccine.
The dataset shows that there were four canine deaths and one feline death following vaccine administration, but two of the dog cases had significant confounding factors. The other two cases involve dogs that collapsed shortly after receiving the vaccination. In addition, three dogs were euthanized following the vaccine.
