Feline Leukemia Virus and Vaccination

When people hear the word "leukemia" they immediately think "cancer". This word had an emotional punch like no other and helps explain the popularity of vaccinating cats against this disease. By doing a bit of research, however, one can soon see that this vaccine may actually produce more harm than good.

Feline Leukemia Virus (FeLV) is a serious disease. At its worst, it can cause malignancies, a suppressed immune system and anemia. Infected cats that do not develop the most serious symptoms will still face a shorter life span due to reduced immune response. Still others will be carriers, never getting sick themselves but able to infect other cats through their nasal secretions and saliva. FeLV is not transmissible to humans.

There are three major problems with the FeLV vaccine. One is that the efficacy of the vaccine, which manufacturers claim is upwards of 80%, just doesn't pan out. In reality, the percentage of cats protected after a regimen of three doses is more like 25% to 50%. A newer vaccine with more concentrated antigen requires only two doses, but doesn't fare much better than the original as far as protection goes. Additionally, studies have shown that although cats in the vaccinated groups do not develop disease, they very often become carriers, shedding the virus that can then infect other cats. This surely is not the result cat lovers expect when they get their pet inoculated!

A very nasty side-effect of this vaccine is the tendency to cause soft-tissue tumors (fibrosarcomas). These malignancies, which most often occur at the site of injection, are difficult to treat as they tend to recur even after removal. They are also very aggressive tumors, presenting very soon after injection and growing very quickly. The inability to treat these vaccine-induced sarcomas means that they are very often fatal.

Obviously, inoculating your cat against one type of cancer only to cause another is worse than an exercise in futility, it is downright dangerous. How do we protect our cats from Feline Leukemia Virus, then? FeLV mostly infects cats younger than 4 months old. If you get your pet from a reliable shelter or breeder, they will test the kitten(s) to be sure there is no infection. If infection exists, the vaccine won't help anyway. If not, then keeping them indoors until they are older will drastically reduce their chances of encountering the virus and becoming infected. Of course, cats that stay indoors for their whole lives (the preferred method!) will never be at risk.

To be continued...Chat later!