FIP was once a death sentence for cats. Antiviral treatments introduced since 2019 now offer cure rates above 85% — a dramatic welfare transformation for cats diagnosed with this previously untreatable coronavirus mutation.
FIP welfare has been transformed by antiviral therapy. Before 2019, a confirmed FIP diagnosis meant imminent death — cats suffered progressive deterioration from effusion, inflammation, and organ failure before euthanasia. The discovery that GS-441524 could achieve remission in the majority of FIP cases is one of the most significant recent advances in companion animal welfare. Treatment requires 12 weeks of daily medication, monitoring, and follow-up, but most responding cats return to full health and normal life expectancy. The primary welfare challenge today is access — GS-441524 remains unlicensed in most countries, requiring owners to source it from compounding pharmacies or grey market suppliers at significant cost. Welfare disparities exist: cats whose owners can afford and access treatment survive; others still face euthanasia. Advocating for licensed, affordable antiviral access for FIP is now a welfare priority for companion animal organisations.