We are now recommending the 1 year Purevax rabies vaccination for our feline patients. Although this may initially seem like a step backward from the 3 year vaccine, we have made this decision for the health of our feline friends. Some cats have a propensity to develop a cancerous tumor (fibrosarcoma) at certain vaccination sites. The risk of this is small, but very real. It is thought that these tumors may be caused by the chemical adjuvant found in certain vaccines. The adjuvant is what stimulates the exaggerated immune response needed to get a sustained reaction from the immune system so the vaccine will result in immunity for up to 3 years. The Feline Purevax Rabies vaccine has been formulated specifically to address this issue and is adjuvant-free. This results in the shorter period of immunity of one year. Although we recognize the inconvenience of an annual vaccine, we feel that the benefit of decreasing the risk of a serious cancer is worth it and have made this a part of the preventive care for all of our feline patients.