02/07/2026
๐ฉ๐ฎ๐ฐ๐ฐ๐ถ๐ป๐ฎ๐๐ถ๐ผ๐ป ๐ฅ๐ฒ๐ฐ๐ผ๐บ๐บ๐ฒ๐ป๐ฑ๐ฎ๐๐ถ๐ผ๐ป๐ ๐ณ๐ผ๐ฟ ๐๐ฎ๐๐ ๐๐ถ๐๐ต ๐๐ฒ๐๐ฉ ๐ฎ๐ป๐ฑ ๐๐๐ฉ
Although both FeLV and FIV affect the immune system, the degree of immunosuppression and vaccination recommendations differ.
Cats with progressive FeLV infection are generally more severely immunocompromised than cats with FIV. Progressive FeLV infection causes broader impairment of the immune system, making it especially important to maintain protection against vaccine-preventable diseases. Vaccine-induced immunity may also be less complete and shorter-lasting.
For FIV-positive cats, the concern is different. In adult, previously vaccinated cats kept strictly indoors, the risk of infection may be lower than the potential harmful effects of unnecessary vaccination. Feline Panleukopenia Virus (FPV) antibody titer testing can help determine whether revaccination is needed.
Vaccine responses may vary with the stage of FIV infection. Cats in the early stages have been shown to mount protective antibody responses, but responses may be impaired in the terminal stage. There is also a theoretical concern that unnecessary immune stimulation could promote FIV replication, although evidence remains conflicting.
Although inactivated vaccines are preferred, this recommendation is precautionary. Pilot studies found no increase in vaccine-associated adverse events (VAAEs) after modified-live FPV vaccination in asymptomatic FeLV- and FIV-positive cats.
These recommendations are intended as a general guide. Vaccination decisions should always be individualized based on the cat's clinical status, stage of disease, previous vaccination history, lifestyle, and risk of pathogen exposure.
Hartmann K, et al. Vaccination of Immunocompromised Cats. Viruses. 2022;14(5):923. European Advisory Board on Cat Diseases (ABCD).
