If you’ve received our health warranty, you may have noticed a clause about the FeLV (Feline Leukemia Virus) vaccine — specifically, that having it administered will void your warranty. This surprises some new kitten owners, and we completely understand why! Your vet may even recommend it at your first appointment, which can make our stance feel confusing. We want to explain our reasoning clearly, because this is genuinely a nuanced topic and your kitten’s health is what matters most to us.
First — what is FeLV?
Feline Leukemia Virus is a serious viral disease that suppresses a cat’s immune system and can lead to anemia, chronic infections, and cancer. It’s spread through direct contact with infected cats — primarily through saliva, shared food and water bowls, mutual grooming, and bite wounds. It is not spread through casual environmental contact; the virus is fragile and doesn’t survive for long outside of a host.
Why this vaccine is considered “non-core” for indoor cats
Veterinary guidelines classify vaccines as either “core” (recommended for all cats regardless of lifestyle) or “non-core” (recommended based on individual risk factors). The FeLV vaccine falls into the non-core category for adult indoor cats. The reason is straightforward: if your cat lives exclusively indoors and never has contact with unknown or outdoor cats, their exposure risk is extremely low. The American Association of Feline Practitioners, Cornell University’s Feline Health Center, and other leading veterinary authorities all agree that indoor-only cats with no contact with FeLV-positive cats have minimal need for this vaccine.
So why does it matter enough to be in our warranty?
This comes down to a well-documented risk called Feline Injection-Site Sarcoma (FISS) — a rare but very serious type of aggressive cancer that can develop at vaccination injection sites. Research has linked adjuvanted vaccines (vaccines that contain an immune-boosting additive called an adjuvant) to a higher rate of this local inflammatory response. Historically, both rabies and FeLV vaccines in the US were predominantly adjuvanted products, and both have appeared in FISS research as inciting causes.
FISS is rare — the American Association of Feline Practitioners estimates the risk at less than 1 in 10,000 doses. But when it does occur, it is a highly aggressive, fast-growing tumor with a high recurrence rate, and it is devastating. For an indoor cat whose lifestyle carries essentially zero FeLV exposure risk, introducing even a small cancer risk for a vaccine they don’t need is, in our view, not a trade-off that makes sense. That’s why reputable breeders commonly include this restriction in their contracts — it’s not arbitrary; it comes from a place of careful research and genuine concern for the cats.
This is your cat and your choice
We want to be completely transparent: once your kitten is home with you, they are yours, and you make all health decisions for them. We are not saying the FeLV vaccine is never appropriate. If your cat ever has outdoor access, lives with cats whose FeLV status is unknown, or is in any situation that introduces exposure risk, the vaccine conversation absolutely changes. In that case, we’d encourage you to discuss it with your vet, ask about non-adjuvanted options like Purevax (which carries a lower FISS risk), and make the decision that’s right for your cat’s specific lifestyle.
What we are saying is that for a strictly indoor Ragdoll with no exposure risk, this is a vaccine most leading veterinary guidelines would call unnecessary — and the injection site risk, while small, is real enough that we ask you to consider skipping it. Keeping your kitten indoors and having any new cats properly tested before introduction is the most effective FeLV prevention strategy available, period.
As always, please talk openly with your veterinarian, share these concerns, and make the decision together. We’re always happy to discuss this further if you have questions!