As with rabies vaccines, most currently available vaccines for FeLV are killed vaccines. The presence of adjuvants, with and without aluminum, has been the target of much speculation regarding the postvaccination inflammatory reaction in cats and, in some cases, the subsequent sarcoma development. Metastasis is common. There is no best way to treat these tumors. Usually, aggressive surgery offers the best hope of control or cure.
Recurrence following surgery is possible.
Vaccination site recommendations have been established by the AAFP and the Vaccine-Associated Feline Sarcoma Task Force. These recommendations are designed to facilitate treatment and to further understanding about the potential causal link between vaccination and tumor development. They are not designed, in and of themselves, to decrease the risk of tumor development. At our present level of understanding this very complex problem, it is clear that for most cats, the benefits of vaccination far outweigh the risk of tumor development. To further identify the causal link and to facilitate treatment, the American Association of Feline Practitioners and Academy of Feline Medicine have established general guidelines for vaccine administration.