Vet Med Today: VAFSTF Report 697 A to the editor published in the Journal of the American Veterinary Medical Association in October 1991 first raised the issue of a potential association between vaccination of cats for rabies and development of sarcomas. At about this same time, the vaccine industry had shifted from production of modified-live virus vaccines for rabies prophylaxis to killed-virus vaccines. This change had been encouraged by the USDAAnimal Plant Health Inspection Service (APHIS) primarily because of concerns about vaccine-induced disease with the use of modified-live rabies virus vaccines. Most killed-virus vaccines contain adjuvants to enhance the immune response, and injection of some killed-virus vaccines has been shown to result in inflammatory granulomas in cats. Some of these inflammatory granulomas to progress to sarcomas. Additional reports, including individual case reports and retrospective epidemiological studies, that supported concerns voiced in the initial letter quickly followed. The weight of these cumulative reports resulted in alarm and controversy in the veterinary medical profession, which continues today. As the evidence for a causal relationship between vaccination for rabies and development of sarcomas grew, it became apparent that a causal relationship between vaccination for FeLV and development of sarcomas also existed. In addition, there appeared to be much smaller, but nonetheless real, associations between development of sarcomas and vaccination for other infectious diseases in cats and between development of sarcomas and injection of nonvaccine products. In response to concerns about this emerging health issue of cats, the American Veterinary Medical Association (AVMA), American Animal Hospital Association (AAHA), American Association of Feline Practitioners (AAFP), and Veterinary Cancer Society (VCS) jointly formed the Vaccine-Associated Feline Sarcoma Task Force (VAFSTF) in November 1996. The mission of the VAFSTF was to plan and execute a coordinated response of research and education to what had become a substantial problem for cats, cat owners, and the veterinary medical profession. The task force was authorized by the sponsoring organizations to address the problem during a 3-year period. Because most sarcomas that developed at injection sites were associated with injection of vaccines, the VAFSTF focused on the issue of sarcoma formation associated with vaccination in cats. The VAFSTF has brought substantial financial and scientific resources to bear on this problem. The task force has provided educational information to veterinarians and the public and funded research to understand the fundamental nature of postvaccinal sarcoma development and how best to treat affected cats. By providing accurate scientific information and funding research, the VAFSTF has kept this problem before the veterinary medical profession and the producers of vaccines and other products meant for parenteral use in cats. The VAFSTF has responded to media and public inquiries, has demonstrated that the profession is addressing the issue, and, thereby, has helped defuse potential adverse publicity. In addition, the VAFSTF, along with other veterinary organizations, has recommended standardized sites for vaccination of cats in the United States and has offered guidelines for the management of injection site masses and sarcomas. The purposes of the present white paper are to present a summary of the current understanding of vaccine-associated feline sarcomas (VAFS) and to describe the activities of the VAFSTF since its inception.

The safety profile of a new controlled-titer feline panleukopenia-rhinotracheitis-calicivirus-Chlamydia psittaci vaccine was compared to that of a currently-marketed vaccine. Of particular interest were delayed reactions (previously unreported in the literature in felines) occurring 7 to 21 days after vaccination, and the effect of concurrent vaccinations and cat age on the delayed reaction rate. Nineteen hundred twenty-four doses of the new vaccine and 364 doses of the comparison vaccine were administered in 42 participating veterinary practices. The postvaccination evaluation period was 21 days. Reactions (anaphylaxis, short- and long-term lethargy, inappetence, pain, upper respiratory inflammation, delayed fever, anorexia, and miscellaneous events) were reported in 3.33% of cats receiving the controlled-titer vaccine and in 3.02% of cats receiving the comparison vaccine. The difference was not statistically significant (P = 0.45). Reaction rate of the controlled-titer vaccine and that of the vaccine currently accepted by veterinarians appear to be equivalent.