Feline infectious peritonitis was until recently a uniformly fatal diagnosis, but antiviral treatments developed from 2019 onwards have transformed outcomes for cats with this devastating disease.
The transformation of FIP from a death sentence to a treatable condition represents one of the most dramatic welfare improvements in veterinary medicine in recent decades. Cats receiving antiviral treatment typically show measurable improvement within days, recovering from conditions so severe that euthanasia had previously been the only humane option. The primary remaining welfare challenge is cost and access: treatment is expensive, and cats belonging to owners who cannot afford the full course may receive inadequate treatment leading to relapse. Regulatory approval of FIP antivirals in more countries would reduce costs through competition and enable wider access to what is now a highly effective treatment.