What is a vaccine associated sarcoma?

A sarcoma is a type of cancer. Vaccine associated sarcoma’s can spread from the site of the injection down into surrounding connective tissue, muscle, and bone. They occur due to repeated inflammation, so technically one could occur from any injection, even a simple antibiotic. However, they are much more commonly associated with adjuvants. Adjuvants are agents put into some vaccines that are designed to cause inflammation, because some degree of inflammation will trigger more of an immune response.

Vaccine associated sarcoma’s can be difficult to treat. In some cases, even with aggressive treatments such as chemotherapy, radiation, and surgical removal some cats have died from. Although vaccine associated sarcoma’s can be deadly, it is important to note that they are rare. About 1 in 10,000 cats given a vaccine containing an adjuvant (most notably FeLV and rabies) will develop a sarcoma.

The Animal Hospital of Chetek uses the safest FeLV vaccine available. It is an adjuvant-free transdermal vaccination. There has been no link between this vaccine and vaccine associated sarcomas.

Finally, even if we did not use the safest vaccines available, we would still recommend vaccinating kittens as there is a far greater risk of contacting FeLV then there is of developing a vaccine associated sarcoma.