Feline Leukemia (FeLV) Vaccine

Feline Leukemia Virus, a retrovirus, is unfortunately a common infection among cats, especially those who are allowed outside. The virus is spread through contact with the saliva, blood, or urine of an infected cat, most commonly saliva or from mother to kitten. It also can be spread through friendly contact. While most infected cats will shed the virus and become immune, cats that do not become immune sicken quickly—85% of cats die within 3 years of diagnosis—and once the virus spreads to the bone marrow there is no effective treatment for the disease. Because of this poor prognosis, prevention is especially important. There are several ways of preventing your kitty from contracting this disease:
The easiest preventive method is simply to avoid exposure. Keep your cat indoors, away from other neighborhood cats and feral cat colonies that are likely to harbor active infections.

1. Screen all newly-adopted cats and kittens for infection. A simple blood test, run in the hospital, can tell us whether or not your kitty has the virus within 30 minutes. Since the virus may not be detectable for 1-3 months after infection, it is recommended that kittens be tested after six months of age, even if tests performed at a younger age show the kitten is negative to be absolutely sure.
2. Vaccinate! Cats are most susceptible to infection with FeLV as kittens, so the AVMA and AAFP both recommend a series of 2 FeLV vaccines for ALL kittens up to 1 year of age, regardless of exposure. This is to be followed by a booster after one year of age for adult cats with continuing risk of exposure.
3. If you decide to keep a kitty who is infected with Feline Leukemia, you should maintain your household as a “closed colony.” In other words, do not introduce any new cats to the house unless they are already infected with the virus too. Luckily, the virus dies quickly once outside a cat’s body, so new, healthy cats may be safely introduced within days of the departure of an FeLV-positive kitty.

For more information, please feel free to call Pet's Friend Animal Clinic about any questions or concerns you may have at 408-739-2688.

Newsletter Signup

Sign up now for more articles


Find us on the map

Office Hours

Our Regular Schedule

Pet's Friend Animal Clinic


7:30 am-6:00 pm


7:30 am-6:00 pm


7:30 am-6:00 pm


7:30 am-6:00 pm


7:30 am-6:00 pm


8:30 am-4:00 pm