Feline Leukemia Vaccinations
Drs. Foster & Smith Educational Staff

Part 2 of 3: Feline Leukemia - Why and How to Vaccinate Part 2 of 3: Feline Leukemia - Why and How to Vaccinate
THE FELINE LEUKEMIA VIRUS (FELV) IS ONE OF THE LEADING CAUSES OF ILLNESS AND DEATH in house cats. Although outdoor cats and indoor/outdoor cats are at greatest risk, indoor cats living in households with FeLV-infected cats or with cats of unknown infection status are also at risk.

Vaccination is recommended for all cats at risk of exposure to FeLV, especially those younger than four months of age. Vaccination is not recommended for cats with minimal to no risk of exposure.

Vaccines may protect against FeLV alone or may be included in a vaccine that protects against a variety of feline diseases. In either case vaccines are 80% to 90% effective in preventing FeLV infection.

Vaccinate against FeLV as early as 8 weeks of age and repeat in 3-4 weeks. Booster at 1 year after completion of initial series and then annually.


Cost of vaccines varies. You may opt to have your veterinarian give them or go to a low-cost vaccine clinic. By far the easiest and least expensive route is to do it yourself.


You give the FeLV vaccine subcutaneously (under the skin) or intramuscularly. Subcutaneous administration is the easiest. For vaccines containing FeLV, vaccinate under the skin low on the outside of the left rear leg.

1 Place needle on syringe and insert it in the liquid vial.

2 Withdraw 1cc (1 ml) of liquid.

3 If a powdered vial is included, inject the liquid into the powdered vial, and shake. Then withdraw contents of vial.

4 Lift the skin into a triangle and inject into the middle of the triangle.

5 That’s it – you have successfully given the vaccine.


Your cat may develop a small, painless swelling at the vaccine site. This should disappear in several weeks. If it persists beyond that, your cat may be developing an invasive and serious sarcoma and should see your veterinarian.

Because FeLV vaccines do not induce protection in all cats, avoiding exposure to infected cats remains the single best way to prevent your cat from becoming infected.

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