Is it safe to introduce an FIV negative cat to a vaccine-positive cat?

Thank you for contacting Petco Pet Education Center, formerly Petcoach with your question about Gimli. He is so handsome! I love that you have adopted an FIV+ cat, many people will not do that. It shows the kind of person you are, very caring. Cats who are FIV- can live with cats who are FIV+ without issue. The method of transmission is through a bite, so if your two cats live peacefully with each other, it cannot be transmitted. The most important thing to do is get your FIV- cat vaccinated again FIV. That will protect the cat from getting it. I have personally heard of a number of mixed households where they lived peacefully with each other. Get your cat fully vaccinated against FIV before integrating them. I hope this helps!

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.

It would be safe to adopt another FIV+ cat. The risk of transmission of FIV is relatively low between cats that are friendly but the safest route would be to find another positive cat. If you decide to adopt another cat make sure to introduce the cats slowly and ensure you have adequate resources for both cats. This is a great source for introducing a new cat into your household: https://icatcare.org/advice/how-introduce-kitten-cat

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.

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.

I would tend to agree with your vet. FIV positive cats do not have a normal immune system, so vaccinating them may not be effective regardless and the vaccine itself can sometimes cause unwanted reactions. If Mikel's life-style is low-risk (indoor only, no new cats added recently to the household), I would not recommend vaccinating him as the downsides probably outweigh the benefits for him.

No. They have done studies on cats that live together and share water bowls and food bowls. The studies show after 10 plus years a few did turn positive but the risk is minimal unless actively fighting one another. As far as Felv, there is more of a risk but it does not live very long in the environment and each room and supplies are disinfected for such viral disease in between each patient. Felv is protective in the vaccine you routinely get to also minimalist the risk