The Benefits and Drawbacks of the FIV Vaccine for Cats

A veterinarian about to vaccinate a kitten

When the FIV (Feline Immunodeficiency Virus) pet vaccine was disclosed in March 2002, the medical world was ecstatic, not just because of its potential utility for cats, but also because it may drive research on a human AIDS vaccine.

The University of California and the University of Florida possess the FIV vaccine patents, which were licensed to Fort Dodge Animal Health, a branch of Boehringer Ingelheim, for production under the name "Fel-O-Vax FIV." This vaccine was pulled off the market in 2015, and it is no longer approved for use in the United States or Canada.

History of FIV and the FIV Vaccine

In 1986, immunologist Janet Yamamoto and Niels Pedersen identified the FIV virus in cats for the first time. Yamamoto began researching on a FIV vaccine at the University of Florida, where she collaborated with experts from Fort Dodge Animal Health. Pedersen, who was the head of the Center for Companion Animal Health, is regarded as a leading authority on retroviruses and small animal immunologic diseases. He credits Dr. Yamamoto's decade-long dedication to the study with the FIV vaccine's licensure.

Potential Concerns

As additional information became available after the FDA approved the FIV vaccination, letters began to circulate around cat rescue groups, highlighting one fatal flaw: all existing methods of testing for the FIV virus will indicate a "positive" for cats inoculated with the FIV vaccine. What this implies for owners and vaccinated cats might have potentially severe consequences. A vaccinated cat might be killed as a FIV-positive cat if it is lost or merely picked up by an animal control officer.

There's no way of knowing which "positive" cat is actually infected and which has merely been FIV-vaccinated. It's no surprise that the vaccination was met with skepticism by the general public, especially in the United States, where FIV affects barely 2% of "at-risk" cats.

The American Association of Feline Practitioners (AAFP) produced a FIV Vaccine Brief in response to many enquiries from and rescue organizations, however they did not make any specific recommendations.

Other Causes for Concern

Although there are five strains of FIV (known as Clades), the vaccine was produced utilizing only two of them. Clade B, which is widespread in the United States, especially in the east, was not one of those two, and the vaccine's effectiveness was not tested against it. This means that even fully vaccinated cats may be vulnerable to FIV.

FIV is a terrifying disease, despite its low prevalence in the United States. While cats can have a long and happy life, it is deadly in the end. While this vaccination was a significant scientific advance with significant potential, it is currently not a feasible method of protection for our kitties.

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.


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