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Question about F.I.V. immunization?

post #1 of 13
Thread Starter 
As some of you may have read a guy I work with surrendered his cat to our shelter this past weekend. She tested F.I.V. positive, but she had had 3 rounds of the F.I.V. immunization shots. I know that this will cause cats to test positive, but I'm intrested in reading more about these shots. My vet never brought these up because my cats are all tested & all stay inside. So I'm wondering if anyone here knows anything about these shots or knows where I can read more about them?
post #2 of 13
my research indicates that the fiv vaccine is of dubious efficacy as it doesnt protect against all strains of fiv. The fact that it causes all cats to test positive for fiv is unfortunate, and as a vaccine that uses an adjuvant it may later cause cancer. It doesn't seem to be a recommended vaccine.
post #3 of 13
I would not have my cats get that vaccine. I had been feeding a stray cat last year (I call him a stray because he was obviously underfed and the property manager called him a stray). When I finally took him in to the vet, he was tested for FIV and FeLV so that I could hopefully find him a good home. Unfortunately, he tested positive for FIV. Because of that plus his general condition (he was an old, sick kitty), and because I couldn't risk letting him back outside where he could infect other cats, he was put to sleep. A neighbor later claimed he was hers (though he was so unkempt and ill that she must have been neglecting him).

To this day, I occasionally wonder whether he truly had FIV or had only been vaccinated for it. If it somehow became necessary to vaccinate my kitties for FIV, I would absolutely have a note added to their ID tags, and to their microchip record as well. If they were to get out and someone found them and had them tested, they could be put to sleep for falsely testing positive for FIV.
post #4 of 13
A feline specialist told me she didn't like this vaccine. She said some cats were probably being put down at shelters without being given a chance because of testing positive. She said it could also possibly cause a false positive on a leukemia test. She also doubted that it gave much in the way of protection.
post #5 of 13
I agree with what everyone has said. I would never give this vaccine. Anything that does a false-positive can be dangerous in case they get loose and end up at a shelter. FIV is tough to transmit unlike FelV. FIV positive cat can live harmoniously with a negative cat without transmission, unlike FelV which is easily transmittable.
post #6 of 13
post #7 of 13


I have a silly question.. if the vaccine shows up as positive for it .. Is there any way to tell via like blood work who really has it or doesnt??
post #8 of 13
Not as far as I know. Thats why the vaccine can be seen almost as dangerous. Shelters won't give it a second look either if there is a chance of a cat having FIV most likely they will be put down.
post #9 of 13
Quote:
Originally Posted by sharky


I have a silly question.. if the vaccine shows up as positive for it .. Is there any way to tell via like blood work who really has it or doesnt??

According to my vet, there is another test that can distinguish between the vaccine and the true disease, but I believe it has to be sent out to a lab and it is probably more expensive, so shelters and the average good samaritan aren't likely spend the extra money and wait the extra time for it.
post #10 of 13
Quote:
Originally Posted by sharky


I have a silly question.. if the vaccine shows up as positive for it .. Is there any way to tell via like blood work who really has it or doesnt??
There are 3 tests to check and see if a cat is Fiv Positive. Because the Fiv vaccination contains antigens that react to the test, so vaccinated cats are more likely to show false positive.
It would be good to know the background of the cat, has she been in contact with any sick cats? Was she an indoor cat only, before going to the shelter?
If she is at a higher risk of having Fiv/Felv, then most likely the ELISA test was used. It is a very sensitive test, so if she has been overly vaccinated, she would most likely show a false positive.
If the test is thought to be wrong, or you would like to confirm the positive results, there are 2 other less sensitive tests that may be used. IFA (immunofluorescent anitbody assay) or the Western blotting test. Either test rarely gives a false positive.
post #11 of 13
Quote:
Originally Posted by sharky


I have a silly question.. if the vaccine shows up as positive for it .. Is there any way to tell via like blood work who really has it or doesnt??
It's not a silly question at all. The answer is no. And that's the worst part about it. There is absolutely no available blood test that differentiates between infected cats and vaccinated cats.

Ironically, FIV infection rarely has a substantial effect on the length or quality of a cat's life. Testing positive for FIV, though, is often a death sentence because FIV+ cats are routinely "euthanized" in almost all shelters and even at many vet practices.

IMNSHO, any vet who recommends the FIV vaccine ought to have his/her license revoked. I truly feel that strongly about the issue.
post #12 of 13
Quote:
Originally Posted by FamilytimeRags
If the test is thought to be wrong, or you would like to confirm the positive results, there are 2 other less sensitive tests that may be used. IFA (immunofluorescent anitbody assay) or the Western blotting test. Either test rarely gives a false positive.
You're right that the test doesn't give a false positive, but the end result is the same - a vaccinated cat will still test positive. It's a true positive because the test has accurately measured antibody levels as it was intended to do, but it is not reflective of the cat's infection or vaccination status.

Infection with FIV rarely causes antigen levels high enough to be detected, so the only tests available - ELISA, IFA, and Western blotting - all check antibody levels. Vaccination causes detectable antibody levels - that is, after all, the whole purpose of vaccination. So the end result is that FIV vaccinated cats will test positive on all available tests because all check for antibodies.

A kitten under 6 months of age who tests positive should be re-tested at 6 months of age because kittens born to infected mothers carry their mother's antibodies, derived from nursing. It is rare for FIV infection to be spread from mother to kitten. Kittens who initially test positive will almost always test negative by 6 months of age. You can re-test earlier than 6 months if you want because usually it is in everyone's best interests for the kittens to be given a clean bill of health as early as possible so they can be better candidates for adoption. Often - but not always - kittens will test negative well before the 6 month mark. A negative test at any point can be considered conclusive, but a positive test indicates re-testing at a later point.

Incidentally, the FIV vaccine is not known to have any efficacy at all against viral subtype B, which is the subtype found in the eastern US. Grrr.
post #13 of 13
Quote:
Originally Posted by SolarityBengals
Not as far as I know. Thats why the vaccine can be seen almost as dangerous. Shelters won't give it a second look either if there is a chance of a cat having FIV most likely they will be put down.
I'd say more dangerous. I know lots and lots of cats with FIV but I don't know any who have died of causes directly related to FIV. But I've known of plenty who have died in shelters and even in vet practices after testing positive.
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