From Franny Syufy,
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What About Vaccine-Related Sarcoma?

Much has been published about vaccine-related sarcoma recently, particularly on the Internet. This anomaly usually occurs resultant from the rabies or more often the FeLV vaccines given. Dr.Greg Ogilvie of Colorado State University, in a lecture on vaccine induced fibrosarcomas in cats, explained a possible link with the use of aluminum in certain vaccines. Dr Ogilvie also mentioned that there is some evidence that a cat must have a genetic predisposition to develop a tumor, which may account for the rarity of the incidence (3 in 10,000 to 1 in 1,000 cats). Because of the difficulty in establishing a clear relationship, the in 1996, the AVMA created the Vaccine-Associated Feline Sarcoma Task Force to study the true scope of the problem, the exact cause, and most effective treatment of vaccine-related sarcomas. Their findings have now been posted, and can be read in the last two links in the sidebar.

FeLV Vaccine

Because of the seriousness of this always fatal disease, and because the FeLV vaccine also carries risks of VAS, special guidelines have been issued for this vaccine. The disease is transmitted through saliva and nasal secretions, by biting, sharing food dishes, and other close contact. All cats should be tested for this disease at least once during their lives, and at any other time when they might have had contact with an infected cat. New cats to a household must always be tested prior to introduction to the environment. All cats with a positive ELISA screening test should be segregated from other cats.

The vaccine is not recommended routinely, but is recommended for all indoor-outdoor cats, and any other cats deemed "at risk." In those cases, it should be given annually, according to the AAFP guidelines. In addition, because of the risk of vaccine-related sarcoma, special vaccination site guidelines have been issued for all recommended vaccines:

Rabies: In the right rear leg
FeLV: Left rear leg
Panleukopenia, feline herpesvirus I, feline calicivirus (or 3-way): Right fore region (shoulder)

The reasoning behind this, unpleasant as it may sound, is that a VAS tumor on the leg can be treated by amputation, allowing affected cats to survive. Cats are wonderfully adaptive, and usually adjust quite quickly to navigating on three legs.

Fears about the possibility of vaccine-induced tumors have led many cat owners, particularly breeders, to refuse the FeLV vaccine for their cats. Presently there is no USDA standard for FeLV vaccines, therefore rating the effectiveness of the vaccines is difficult. Many veterinarians estimate the effectiveness to be between 75-85%, which lends some cat owners a reason to deny the vaccine. Personally, I'd rather risk the one in 1,000 chances of vaccine-related sarcoma against the 25% risk that the FeLV vaccination would not work. FeLV is such a deadly disease, so easily transmissable, that I would not want to put my cats' lives up against a statistical roulette wheel.

However, since my cats are considered "at risk," because the oldest one is still an indoors-outdoors kitty, the decision was an easy one for me and my veterinarian. People with entirely indoors cats may want to strongly consider eliminating this vaccination, after discussing the pros and cons with their own veterinarian, but testing should be done any time their cats come in contact with other "suspect" cats.

The New FIV Vaccine

This relatively new vaccination, approved for sale by the FDA on March 14, 2002, has met with resistance and controversy among both veterinarians and lay persons, for a number of reasons. For a more thorough discussion about the pros and cons of the FIV vaccine, see the companion article, "The FIV Vaccine - Friend or Foe?"

Next > Multivalent Vaccines