A very small percentage of cats can develop a malignant skin tumor, called a sarcoma, associated with vaccine injection. Veterinarians began observing this about 15 years ago after the leukemia vaccine became available and when cats were more regularly vaccinated for rabies due to the epidemic.
Both vaccines have been implicated. Despite years of research there are still many unanswered questions. A sarcoma is more likely to occur if multiple vaccines are given in one site (a practice no longer done) and some cats may have a genetic predisposition.
The development of a sarcoma is rare, so the benefits of vaccination and disease protection still outweigh any risks. Within the last few years a non-adjuvanted rabies vaccine became available. Non-adjuvanted means the vaccine has no chemical in it which typically helps the vaccine last longer but also causes inflammation at the vaccine site. Some researchers feel inflammation is the cause of sarcomas, so less inflammation may mean less sarcomas. Yet others point out that this has not been proven, and sarcomas are probably related to multiple factors besides inflammation.
Our feline leukemia is a non-adjuvanted vaccine (Purevax). This reduces inflammation and makes vaccine reactions less likely.
We offer both the Purevax (non-adjuvanted) rabies vaccine which is given yearly and the traditional 3 year adjuvanted vaccine. We believe both vaccines have their place and will be happy to discuss this with you further.