Noncore Vaccinations for Cats

The veterinary community has divided vaccines into two main categories, with a smaller third category. Core vaccines are vaccines that every cat should have at some time in his life. Noncore vaccines are vaccines that only some cats need, depending on factors such as geographic location and lifestyle. Other vaccines are also available but are generally not recommended for any cats.

Feline Leukemia Virus (Noncore)

The development of a vaccine against retroviral infection is a long-awaited achievement in veterinary medicine. However, this vaccine is not 100 percent effective. It is possible that some cats vaccinated for FeLV may still become infected.

This vaccine is noncore because of its incomplete effectiveness and because indoor cats who have been tested before coming home should have minimal risk of acquiring FeLV and therefore should not need this vaccine. Kittens born to immune queens acquire protective antibodies in the colostrum of the queen. This protection begins to disappear at 6 to 12 weeks of age, after which kittens are susceptible.

Cats with access to the outdoors or who roam free may need this vaccine. However, since kittens are most susceptible to FeLV and may escape, some veterinarians recommend vaccinating kittens and giving a first booster at 1 year. If the cat is then firmly established as an indoor-only cat, no more boosters are needed.

Testing for FeLV is recommended before vaccination. Vaccination is not effective if the cat is positive and already infected. If the ELISA test is negative, vaccinate kittens at 8 to 12 weeks of age and again at 14 or 16 weeks. The first booster is given one year later.

To be effective, a full course of vaccination must be administered. This involves two vaccinations two to three weeks apart, a booster a year later, and then annual boosters, if needed.

Vaccines available include injectable adjuvanted killed virus, nonadjuvanted recombinant for transdermal use, and, in Europe, a nonadjuvanted recombinant for subcutaneous injection. According to recommendations of the Vaccine-Associated Sarcoma Task Force, FeLV vaccines are administered subcutaneously as distally as possible in the left rear limb.