Vaccine-associated feline sarcoma (VAFS) is a rare but serious cancer at injection sites, requiring injection site protocol changes to reduce risk.
VAFS is a life-threatening complication of vaccination that causes significant suffering and often death. The welfare response is not to abandon vaccination (which prevents far more suffering than VAFS causes) but to minimize risk through injection site protocols that allow curative amputation if VAFS develops. Owner awareness of the need to monitor injection sites and report persisting lumps is critical for early detection. The WSAVA guidelines represent best current practice for minimizing both VAFS risk and post-VAFS treatment options.