Comparative vaccine-specific and other injectable-specific risks of injection-site sarcomas in cats.

Journal of the American Veterinary Medical Association September 1, 2012;241(5):595-602.

Anup Srivastav; Philip H Kass; Lawrence D McGill; Thomas B Farver; Michael S Kent

Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616, USA.


Article Abstract

Objective-To compare associations between vaccine types and other injectable drugs with development of injection-site sarcomas in cats.

Design-Case-control study.

Animals-181 cats with soft tissue sarcomas (cases), 96 cats with tumors at non-vaccine regions (control group I), and 159 cats with basal cell tumors (control group II).

Procedures-Subjects were prospectively obtained from a large pathology database. Demographic, sarcoma location, basal cell tumor, and vaccine and other injectable history data were documented by use of a questionnaire and used to define case, control, and exposure status. Three control groups were included: cats with sarcomas at non-vaccine sites, cats with basal cell tumors, and a combined group of cats with sarcomas at non-vaccine sites and cats with basal cell tumors. (2) tests, marginal homogeneity tests, and exact logistic regression were performed.

Results-In the broad interscapular region, the frequency of administration of long-acting corticosteroid injections (dexamethasone, methylprednisolone, and triamcinolone) was significantly higher in cases than in controls. In the broad rear limb region, case cats were significantly less likely to have received recombinant (non-adjuvanted) vaccines than inactivated (adjuvanted) vaccines; Odds Ratios from logistic regression analyses equaled 0.1, with 95% confidence intervals ranging from 0 to 0.4 and 0 to 0.7, depending on control group and time period of exposure used.

Conclusions and Clinical Relevance-This case-control study measuring temporal and spatial exposures efficiently detected associations between administrations of various types of vaccines (recombinant (non-adjuvanted) vs inactivated (adjuvanted) rabies) and other injectable products (ie, long-acting corticosteroids) with sarcoma development without the need to directly measure incidence. These findings nevertheless also indicated that no vaccines were risk free. The study is informative in allowing practitioners to weigh the relative merits and risks of commonly used pharmaceutical products.


Plain English of the statistics here:

Cats given killed, adjuvanted vaccines were  10 times MORE likely to develop cancer than cats given recombinant (non-adjuvanted) vaccine. The range (mean +- 2 standard deviations) went from 2.5 times more likely to infinitely times more likely to develop sarcoma if given killed adjuvanted vaccines.