Feline Infectious Peritonitis (FIP) was historically uniformly fatal. Antiviral treatments approved since 2021 are now saving the majority of affected cats, transforming welfare outcomes.
The transformation of FIP from a universally fatal diagnosis to a treatable condition represents one of the most significant companion animal welfare advances of the past decade. The welfare implications are profound: cats who previously faced inevitable death within weeks now have an approximately 85-90% chance of remission with treatment. The welfare costs of treatment include daily injections or oral medication for 12 weeks, veterinary monitoring visits, and in some cases significant expense. The welfare benefit — survival and return to normal life — vastly outweighs these costs for owners who can access and afford treatment. Welfare concerns remain around the diagnostic challenge (some cats receive treatment for conditions they do not have), the variable response rates depending on FIP form, and the financial accessibility of treatment across different income levels.