Feline rabies vaccination side effects

Cat vaccination reaction - photo by Jerry7171 - correct place?

This post concerns the USA. Legislation (law) at national and state level sets out rabies vaccination requirements. Rabies vaccinations should be administered by a veterinarian and this is obligatory in many states.

The recommendations of the Vaccine-Associated Sarcoma Task Force state that rabies vaccines are administered subcutaneously as distal as possible in the right rear leg. Injected "subcutaneously" means injected into the the layer of skin directly below the dermis and epidermis. "Distal as possible" means the farthest away from the center of the body.

There is a link between vaccinations and sarcoma development. This is a possible side effect of a rabies vaccination. A "sarcoma" is cancer in connective and soft tissue. There is a higher than usual risk that this will happen when vaccinating against rabies.

Despite the higher risk sarcomas associated with vaccines for cats is still very rare at one case in 1-10,000 vaccinations.

Some cats are predisposed to the problem. The cause is not altogether clear. It was thought to be due to the aluminium "adjuvant". An adjuvant is substance that is added to improve the immune response. However, investigating the cause is still work in progress.

Sometimes a lump will form after the vaccination. It should go within a month. If not a vet should be consulted.

Giving a cat a vaccine is decided on a balance of risks if there is a choice (i.e. no statutory obligation). Vaccinations should be minimized and older cats might not require vaccinations, particularly full-time indoor cats.