One of the most dangerous infectious diseases in cats today is caused by feline leukemia virus (FeLV). Feline leukemia is a retrovirus that causes suppression of the immune system, impairing a cat's ability to fight infections. It may also cause anemia, leukemia and some forms of cancer. It is a contagious disease spread from cat to cat by blood and saliva. The most common method of spread is by bite wounds.
Cats at risk for developing feline leukemia include outdoor cats, cats living in multiple cat households and cats that interact frequently with other cats. For these high risk cats, vaccinating for feline leukemia may be beneficial.
Prior to vaccinating for feline leukemia, cats should be tested for the virus. FeLV is easily diagnosed by a simple blood test. Once a cat tests negative, the vaccine can be administered.
The purpose of the vaccine is to create immunity in the attempt to prevent infection with the virus. Although no vaccine is 100 percent effective, the vaccine does offer immunity to most cats.
There is both an injectable and a "needleless" transdermal version of the feline leukemia vaccine. The recommendation for both types is similar. The first dose of vaccine is recommended at 8 to 10 weeks of age, a booster is given 3 to 4 weeks later, and a final booster one year later. After that, annual vaccination is recommended.
If your cat lives strictly indoors, you may want to discuss the need for FeLV vaccine with your veterinarian. FeLV vaccinations have been implicated in the rare but very significant inject-site sarcoma syndrome.