Is it safe to vaccinate a cat for feline leukemia if they have FeLV?

Hi and thanks for using PetCoach! Sorry to hear about Boots. I have never personally heard that for Feline Leukemia. The vaccines for FeLV do not cause a positive test result BUT previous FIV (Feline Immunodeficiency Virus) vaccines cause a positive test result that cannot be differentiated from a natural infection. One positive FeLV test in a healthy cat is always suspect. False positives do occur and if you really want to know, I would advise that you go get a confirmation test done at your veterinarians office. The test is called an IFA or Immuno Fluorescent Antibody test and this is specific for FeLV. This disease along with FIV are very complex and sometimes very confusing with respect to the results. Let me provide a website link here so you can learn more about these retroviruses in cats. Good luck with Boots. https://www.catvets.com/guidelines/practice-guidelines/retrovirus-management-guidelines

It is obviously up to you about mixing the cats. I personally do not recommend mixing feline leukemia cats with negative cats. Even though they are vaccinated not all vaccines are 100%. The positive cat is still putting the negative cats at risk. They can spread leukemia by sharing water bowls, food bowls, litter boxes and standard grooming.

Most veterinary internists advise vaccinating FeLV positive cats just like any other cat - they are not at higher risk for vaccine-related problems, and the vaccines are just effective in them as they would be in any other cat. She doesn't need an FeLV vaccine, obviously, but there's no reason she can't be vaccinated normally for RCP and rabies :)

Vaccines are protective but cannot offer 100% guarantee. I would not recommend very close contact, mutual grooming or sharing of food bowls etc. Rigorous flea prevention and keeping them in separate rooms may be the safest option

Feline leukemia is spread mostly by fighting and breeding and most mature cats have some natural immunity. There is always a risk if you haven’t had the kittens tested so I would request a Felv/Fiv test and if they are negative then your cat should be safe to play with them. I don’t wait until they are six months to test kittens. Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for Munchie.

Try not to worry too much as it is incredibly unlikely that this vaccine will cause any issues with Lolly. The amount of virus in these vaccines is only enough to stimulate the immune system but not to actually cause the disease itself. For Lolly to infect the other are she would have to have the disease. Personally I vaccinate all cats for felv regardless of whether they go outside just in case they were to escape from the house etc. The vaccine won't do her any harm, but it is of course your decision whether you want her to have it or not, I imagine your vet made a mistake in giving it because it is so often done in the routine.

FIV and FeLV are two separate conditions. The main reason I recommend and FeLV vaccine is only for cats that will be spending time outside. If you have an FIV positive cat, it is not recommended that he spend any time outside at all since he will be at risk of spreading his disease to other animals. That being said, if he will be indoor only, it is probably not necessary unless you have other cats inside your house that might be exposed to FeLV.