Risks and Benefits of Feline Leukemia Shots

Ann Roberts
Cat and Vet

Most veterinarians recommend feline leukemia shots to prevent the spread of this highly contagious retrovirus, but some pet owners are unaware of the risks associated with the vaccine. In many cases, the benefits far outweigh potential side effects, but it's important to be informed before you make this decision for your pet.

About Feline Leukemia Shots

It used to be that feline leukemia vaccinations were recommended by veterinarians for all cats. After a kitten has undergone its kitten shots, the feline leukemia vaccine was optimally recommended as an annual shot. However, more knowledge and research has been done on the FeLV vaccine since its inception. It turns out that the FeLV shot involves some risk for developing cancer.

The FeLV vaccine is currently thought to be between 75 to 85 percent effective at warding off the effects of the feline leukemia virus. However, it carries a substantial risk of causing a certain cancer called "sarcoma" in cats. Sarcomas are cancerous tumors that require invasive efforts to remove. In fact, many times these tumors cannot be removed and prove fatal to the cat. The FeLV vaccine is not the only vaccine implicated in vaccine-related sarcomas, but it is a vaccine that is no longer considered necessary for all cats.

Due to the risk of vaccine-related sarcomas and other possible side effects, the FeLV vaccine is now being recommended by veterinary experts for only "at-risk" cats. If your cat's lifestyle does not pose a reasonable risk for contracting the feline leukemia virus, your vet should not administer the vaccine to your cat.

Which Cats Are at Risk?

Most veterinarians and animal rights groups recommend keeping domestic cats indoors, particularly if you live in a city environment. Keeping your cat indoors greatly reduces your cat's ability to acquire the numerous communicable diseases that inhabit the feline world. Feline leukemia is spread from cat to cat and is easily contracted in the outdoor environment. Cats that remain indoors with their owners have very little chance of picking up FeLV. If you own an indoor animal that is never exposed to other felines, there is really no need to vaccinate for FeLV.

Keeping your pet indoors is not always enough. If you are bringing in animals from shelters and introducing outside cats into the house for the purposes of rescue efforts, you will likely need to vaccinate for FeLV. Unless any future pet cats have been issued a clean bill of health, they are a potential threat to your current cat.

Weighing the Costs

Animals that lead a high-risk lifestyle should be vaccinated, but pet owners should always inquire as to the specific side effects of a vaccine. Running a little Internet research can also be valuable regarding the pet inoculation process because these routine procedures are not without controversy. As mentioned previously, the FeLV vaccine is not the only vaccine that has been implicated in causing cancer. The rabies vaccine has produced similar findings as well.

Cancer is not the only potential side-effect. Any pet can have a negative reaction to the vaccination process. This can occur due to a faulty immune response or as a result of certain agents within the vaccine. There is no real way to know ahead of time whether a normally healthy cat will be one of the few who suffers a negative reaction.

The only method of circumventing such issues is to lower your cat's environmental risk of contracting the diseases for which vaccinations are recommended. Naturally, this involves keeping your cat strictly indoors. Such methods aren't foolproof. Your cat may escape outdoors for a short duration, and this is all that is necessary for contracting FeLV. However, it is important for pet owners to weigh the costs and consider the risks and statistics to determine if administering the FeLV vaccination is the safest and wisest course of action for their pet.

Risks and Benefits of Feline Leukemia Shots