Post-vaccinal masses in cats: Help Wanted!

Drs. Dennis Macy and Jacqueline Whittemore at Colorado State University are currently seeking clinics for enrollment in a study regarding development of chronic post-vaccinal injection site reactions. This study is being funded through the Vaccine-Associated Feline Sarcoma Task Force.

The duration of post-vaccinal granulomas following vaccination with adjuvanted vaccines is not actually known. The fact that these granulomas cannot be easily differentiated from tumors that arise from vaccine sites has been troublesome. As one to 10 per 10,000 cats will develop a sarcoma at a site of rabies or FeLV vaccine administration, accurate assessment of post-vaccinal masses is very important. The Vaccine-Associated Feline Sarcoma Task Force’s (VAFSTF) guidelines for management of post-vaccinal local reactions were established based on clinical experience in the absence of systematic clinical evaluation of post-vaccinal granulomas. This study will determine the natural behavior of vaccine-associated granulomas and if current guidelines are appropriate or need to be modified.

We are seeking to recruit clinics for inclusion in the study. Each clinic would be responsible for vaccination of up to 48 cats routinely presented for vaccination with the specified rabies [Defensor (Pfizer Animal Health), Imrab 3 (Merial), and Rabvac 3 (Fort Dodge)] and/or FeLV vaccines [Leukocell 2 (Pfizer Animal Health) and Fel-O-Vax Lv-K (Fort Dodge)] within a 30 day period. One cat cannot be evaluated for more than one vaccine. Upon client enrollment, a one inch area of hair from the future vaccine injection site will be clipped and skin thickness measured prior to vaccination. Clients will be required to return for injection site evaluation every 21 days for up to 12 weeks post-vaccination. Should a mass develop that meets the VAFSTF guidelines for biopsy, it should be biopsied appropriately and submitted to us for analysis.

Veterinary clinics will receive $75 per cat, of which $25 will be remitted to the owner, after the PI has received the correctly completed official VAFSTF individual data sheets. The remaining $50 will be used to cover clinic costs. Veterinary clinics will receive $150 per case for surgical removal and submission of any injection site nodules requiring excision to the PI.

Reviewed 12/5/05