Are Vaccines Given In The Tail Safer For Cats?

Jennifer Coates, DVM
Published: November 12, 2013
Are Vaccines Given In The Tail Safer For Cats?

What do you think about vaccinating your cat in the tail? If your initial reaction was like mine you probably squirmed and thought, “No way would she put up with that.” In fact, a pilot study published in the Journal of Feline Medicine and Surgery demonstrated that vaccinations given in the tail were well-tolerated by cats and resulted in an excellent immune response.

The impetus behind this research is the fact that in rare instances, vaccinations (and other types of injections) can cause cats to develop a highly aggressive type of cancer at the injection site. The authors of this study cited a rate of 1-10 cats out of every 10,000 vaccinated. Even though injection site sarcomas are not all that common, they are devastating when they occur. The only hope for a cure is to remove the mass and as much surrounding tissue as possible.

This presented a problem when veterinarians gave most vaccinations under the scruff of a cat’s neck. There is simply little chance of getting wide enough surgical margins in this area before you start running into vital structures. Because of this, most veterinarians switched to giving vaccinations low down (below the elbow or knee) on cats’ legs. If a sarcoma did develop, we could then amputate the leg and give the cat the best chance of survival possible.

In theory, this is a good plan. We gave each vaccine in a particular location so we could monitor which was responsible for any sarcomas that did develop, and veterinarians knew that feline “tripods” do exceedingly well after surgery. The reality was less than ideal, however. Many cat owners balked at the combination of expense, disfigurement, and a still guarded prognosis associated with limb amputation for injection site sarcomas. A better option was needed that would allow cats to benefit from vaccines while providing a more reasonable treatment option in the unlikely event a sarcoma did develop.

Enter the tail. Sixty cats were enrolled in the study. Thirty-one received rabies (RV) and panleukopenia (FPV) vaccines in a hind leg, below the knee and 20 received the same vaccines toward the back end of the tail. The researchers used a six-point scale (1 = no reaction, 6 = injection not possible) to assess the way in which the cats reacted to being vaccinated. They found “no significant differences” in the cats' reactions to receiving injections in the tail versus the leg. In fact, in a poster presented at the American College of Veterinary Internal Medicine meeting this year, the authors reported that “More cats accepted tail vaccination with a low behavioral reaction score of 1–2 (95%) than hind limb injection (78%) (p = 0.03).”

The researchers also collected blood samples from the cats to ensure that tail vaccination stimulated a good immune response. They found that “Of the cats seronegative for FPV at the time of vaccination, 100% developed protective antibody titers (≥40) against FPV 1-2 months following vaccination. For cats seronegative for RV, all but one cat (tail vaccine) developed acceptable antibody titers (≥0.5 IU/ml) against RV.”

I’m not sure how quick (or even if) the veterinary profession will be to start vaccinating cats in the tail, but if you see your veterinarian doing so, you’ll now know why.

Dr. Jennifer Coates

Image: Maryna Kulchytska / Shutterstock

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