How Often Do Cats Need the FeLV Vaccine? A Guide for Pet Owners
Feline leukemia virus (FeLV) is a contagious and potentially deadly condition that affects only cats. Fortunately, vaccinations can dramatically reduce the risk of infection. Yet many pet owners still wonder: how frequently should their furry companions be vaccinated for FeLV? This comprehensive article explores the answer, considering lifestyle, age, exposure risk, and recent veterinary recommendations.
Understanding FeLV and Its Impact
FeLV is a viral disease that suppresses the immune system, causes anemia, and may lead to cancers like lymphoma. It spreads through saliva, especially via behaviors like grooming, bite wounds, or sharing bowls—and from infected mothers to kittens. Because it compromises the immune system, infected cats often suffer from chronic infections and illness.
How the Vaccine Works
FeLV vaccines stimulate the cat’s immune response to resist actual infection if exposed to the virus. Newer formulations, including RNA-based vaccines, offer up to 85% protection and remain effective for up to two years after the initial series.
Recommended Vaccination Schedule
- Kittens: Begin at 8–12 weeks of age with two doses, spaced 3–4 weeks apart.
- Adult at-risk cats (e.g., outdoor cats, multiple-cat households): Annual boosters are advised after the initial series.
- Indoor-only adult cats with no exposure risk: May not require further boosters after initial series. Vaccination becomes non-core in such cases.
Who Should Get the Vaccine?
- Cats that go outdoors
- Cats living with other cats of unknown FeLV status
- Cats living in shelters or foster homes
- Newly adopted cats or kittens
Veterinarians typically suggest testing for FeLV before vaccination, especially if the cat's status is unknown. There is no benefit in vaccinating cats already infected with FeLV.
Booster Timing Based on Risk
Not all cats require the same vaccination frequency. Here’s a breakdown:
- High-risk cats: Annual revaccination is essential due to consistent exposure risk.
- Low-risk cats: Indoor cats with no known exposure may require revaccination only every 2–3 years, or not at all after the initial series.
- Re-evaluation: Your veterinarian may adjust the schedule based on a cat’s changing environment and health status.
Efficacy and Safety
While no vaccine offers 100% protection, those for FeLV significantly reduce the risk of persistent infection. Side effects are rare and usually mild, including:
- Soreness at injection site
- Fever
- Lethargy
In rare instances, cats may develop injection-site sarcomas (fibrosarcomas), but the benefits of vaccination outweigh the risks for most at-risk felines.
Final Thoughts
FeLV vaccination plays a central role in protecting feline health, especially for kittens and at-risk adult cats. As recommendations vary based on lifestyle and risk exposure, it's essential to consult your veterinarian about the appropriate vaccination schedule for your pet.
By following expert guidance, you can help ensure your cat lives a longer, healthier life—free from the shadow of FeLV.





