The Only Right Choice for Your Cat

In the 1990s, researchers discovered that between 1 in 10,000 to 1 in 1,000 vaccinated cats developed an aggressive fibrosarcoma (a type of cancer) near the site of vaccination. Vaccine-associated sarcomas in cats became the most significant adverse reaction linked to common feline vaccines. At that time, rabies and feline leukemia vaccines both contained adjuvant. Over the next ten years the relationship between adjuvanted vaccines and fibrosarcoma was established. An adjuvant is a chemical added to a weak vaccine to make it stronger. Unfortunately, when given to cats, adjuvants produce chronic inflammation of the skin and the muscle. In a few cats, these areas of inflammation transform into cancer. Cats receiving adjuvanted vaccines are five times more likely to develop sarcomas than cats vaccinated with non-adjuvanted vaccines.

During the next decade, vaccines were developed that produced excellent immunity without the need for adjuvant. This was made possible by the development of recombinant technology. Scientist took the genes from a pathogenic virus and placed it in a transport virus (a non-pathogenic virus). Non-adjuvanted vaccines have been shown to markedly reduce or eliminate inflammation associated with vaccination.

Currently, of the fourteen rabies vaccines available in the United States, there is only one adjuvant-free rabies vaccine and that is PureVax^®. It is the only type of rabies vaccine used at The Cat Clinic of Stillwater. Recently, adjuvant-free PureVax® feline leukemia vaccine was introduced. It is a unique product that is administered transdermally using a device that allows needle free vaccination.

Prominent veterinary researchers recommend that veterinarians limit the selection of feline vaccines to non-adjuvanted biologicals. Unfortunately, many owners, breeders and veterinarians continue to use adjuvanted products. The number of cases of vaccine-induced sarcomas is no longer climbing, but the condition is still far too common. There is no national registry for the condition, so the actual numbers are unknown.

The Cat Clinic of Stillwater uses only non-adjuvanted vaccines, because they are the best choice for cats. For us, it is an ethical as well as medical issue. As veterinarians, we have an ethical and moral obligation to avoid products that might cause serious complications.