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    Feline lukemia shot/test
    An_260905 posted:
    Took our newly aquired 14 week old kitten to the vet today. He had 3 shots given. One of those being a feline leukemia shot. Now, beforr i went in there for the appointment i asked him to test the cat for leukemia beforr we proceeded with any other shots or surgeries. [br>[br>When i got in there, hes an old guy and did alot of mumbling. Anyhow, he gives my litten 3 shots without taking any of its blood for a feline leukemia test. Now hes telling me to come back in next week, so he will take blood then....and send it off to be tested. [br>[br>Seems backwards to me. Wouldnt the kitten now show positive for feline leukemia after being given the vaccine? After all most vaccines are dead viruses to build immunity. I could be ALL wrong, im not a vet. Just seems[br>[br>...odd.
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    srstephanie responded:
    Hi An_260905,

    I agree that your vet is not following the recommendations of either the experts who wrote the 2013 AAFP Feline Vaccination Guidelines
    or those who wrote the 2008 AAFP Feline Retrovirus Management Guidelines .
    Both documents recommend that all kittens/cats be tested for FeLV prior to vaccination.

    However, the recommendation for pre-testing is not because the vaccine will cause a false positive. Rather the reason is that if a cat does have FeLV, then the vaccine is of no benefit. Giving it won't hurt, but if already infected, the vaccine will not help.

    As for the vaccine causing future tests to be falsely positive ... that does not appear to be the case. I'm not a vet, but one of the co-authors of the AAFP Vaccination Guidelines, Dr Richard Ford (emeritus at NC State), is a friend and mentor. I've spoken to him often about this. He actually did some studies with FeLV vaccines to see if they would cause a false positive on FeLV tests. His studies showed that they do not cause false positives. The Retrovirus Guidelines do say that there "might" be some false positives for a week or two after vaccination ... but there doesn't appear to be any published study to support that. I think it is more of a cautionary statement.

    Here are a few comments about FeLV vaccines and tests that you or others may not know.

    1. There are two types of FeLV vaccines on the market. As you mentioned, all are Killed Virus (aka "inactivated") ... EXCEPT for one FeLV vaccine which is recombinant. That is a very important distinction and many/most recommend using the recombinant vaccine when possible. Recombinant vaccines are made by using a live carrier virus (called a "vector") ... then taking just a small piece of FeLV DNA (not the whole virus) and inserting it into the vector virus. The only available recombinant FeLV vaccine (Merial's Purevax rRabies) uses the canarypox virus as a vector. It is unique because it is a bird virus that cannot replicate inside a mammal. So, the live recombinant canarypox is injected into the cat. But when it tries to reproduce, it breaks apart and delivers the small piece of FeLV DNA that stimulates the production of protective antibodies to FeLV. Recombinant vaccines do not contain the entire virus ... so, it is impossible for a cat to get FeLV from the vaccine. One big advantage of recombinant vaccines over killed is that recombinant vaccines do not contain any adjuvant ... which the killed vaccines need in order to get the immune system to respond to a dead virus. Adjuvants work by creating chronic inflammation at the vaccination site ... and it is known that chronic vaccination can lead to a deadly cancer (fibrosarcoma) in a small number of cats. There is a well known history of cats developing cancer at the vaccination site after a killed-virus FeLV vaccine. While some claim it is a small number ... when it is your cat, the percentage is unimportant.

    2. All of the tests for FeLV look for antigen (part of the actual virus) and NOT for antibodies. So, while cats will develop FeLV antibodies after vaccination, they will not cause a false positive with any FeLV test. That is in contrast to the other common retrovirus, FIV. Tests for FIV do look for antibodies, and cats that have been vaccinated for FIV will test positive, whether or not they have the virus. It is unknown how long the FIV antibodies will remain, but it is thought to be at least several years. That is one reason (among others) that the FIV vaccine is not often given and generally not recommended by most.

    3. There is an in-clinic FeLV SNAP test that most vets use as an initial test, and only send to a lab when they have a reason to doubt the results.

    Hope that helps.

    Stephanie in Raleigh
    petziti replied to srstephanie's response:
    Hi An_260905

    This article will help you to get read of feline lukemia for your cat

    Petziti - Know Your Pets

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