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Another Reason to Think Twice About the Feline Leukemia Vaccine

Another Reason to Think Twice About the Feline Leukemia Vaccine

Story at-a-glance -

  • A delivery device for a popular feline leukemia (FeLV) vaccine has received an FDA warning about the potential for leg fractures.
  • Two and possibly three kittens have suffered broken femurs through what appears to be inappropriate use of the vaccination equipment.
  • Only kittens and adult cats at real risk for exposure to the feline leukemia virus should be considered for vaccination.

By Dr. Becker

Very recently, the FDA issued a warning to veterinarians about the risk of fractures from use of the Vet Jet vaccination device, which is sold exclusively to deliver Merial's PUREVAX recombinant feline leukemia (FeLV) vaccine.

What prompted the warning were three adverse events reported to the FDA, all involving kittens. In two of the incidents, the kittens suffered fractures of the femur as a result of use of the Vet Jet device. Per the FDA, in those two incidents, the user "failed or may have failed to properly lock the nozzle into the device before using it."

Merial is busy investigating the three cases, revising Vet Jet instructions to emphasize the necessity of locking the nozzle into place, and sending letters out to all users of the device.

Putting aside the fact for a moment that I'm not a fan of feline leukemia vaccines, it is incredibly disturbing to know a device used to deliver the shot can so easily fracture the leg of a tiny kitten.

Before You Agree to a Feline Leukemia Vaccine for Your Cat ...

You must assess your kitty's real risk of contracting the disease.

From the Winn Feline Foundation:

The American Association of Feline Practitioners has released feline vaccination guidelines. They divided vaccines into core and non-core groups. Core vaccines are those felt to be necessary for all cats and non-core vaccines are felt to be necessary only for those cats at realistic risk of the disease. FeLV vaccines are designated as non-core vaccines.

Vaccination is recommended only for those cats whose lifestyle places them at risk for FeLV. This includes outdoor cats or those that are indoor/outdoor, feral cats, cats in open multi-cat households, cats in FeLV-positive households, and cats in households where the FeLV status of all resident cats is not known. Since young cats are at the greatest risk and their lifestyle is most likely to change in the future, the AAFP panel felt that it may be appropriate to suggest initial FeLV vaccination for all kittens, with subsequent annual vaccinations only for those that continue to be at-risk.

In any case, owners should discuss issues of FeLV testing and vaccination with their veterinarian so the best decision can be reached for each individual cat.

I disagree with the AAFP that it may be appropriate to vaccinate all kittens against FeLV, regardless of exposure risk.

Kittens and young cats are at a greater health risk than adult cats if they acquire the disease, but in the case of non-core vaccines, which includes those for FeLV, it is the potential for individual exposure that should decide whether vaccination is appropriate.

Assuming a kitten's lifestyle will change in the future from 'no exposure' to 'risk of exposure' is to assume the kitten will wind up at a shelter, on the street, or with an irresponsible owner -- an offensive assumption to those of us who are committed to caring for our cats for the rest of their lives.

From the University of California, Davis:

We recommend vaccination of FeLV-negative cats allowed to go outdoors or cats having direct contact with other cats of unknown FeLV status. Vaccination is most likely to be useful in kittens and young adult cats, because acquired resistance to infection develops beyond 16 weeks of age. As of 2006, the AAFP recommends primary vaccination of all kittens for FeLV, but the decision to administer booster vaccines is based on risk assessment. Vaccination is not recommended for FeLV-positive cats and indoor cats with no likelihood of exposure to FeLV.

Because of concerns relating to sarcoma formation following administration of killed, adjuvanted vaccines, we currently stock and suggest the use of the recombinant transdermal FeLV vaccine.

Certain FeLV vaccines are one of two types of vaccinations linked to vaccine-assisted sarcomas in cats, which is why UC Davis recommends only the recombinant transdermal variety.

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Prevention of Feline Leukemia

The best way to prevent feline leukemia in your cat is to make sure he isn't exposed to any other kitty with the virus.

Keep him indoors. If you want to let him outside, either provide non-stop supervision or confine him so that no other cat can scratch or bite him.

Don't allow him to interact with FeLV positive cats, or cats of unknown health status.

If you have FeLV positive cats in your care, make sure they are housed separately from uninfected kitties.