Epsilon Archive for Student Projects

Abstract

There is a debate concerning adverse reactions following vaccination of companion animals which has been ongoing for years. Every year a number of suspected vaccine-associated adverse reactions are reported to the appropriate government administrations across the world. Many of these are mild, such as lethargy and irritation at the injection site but some are more severe in nature, namely feline injection site sarcomas and anaphylactic shock. The cause of injection site sarcomas is not completely clear. However, studies have shown that they are often preceded by a severe inflammatory response in the tissue following an injection. Though this may be caused by any type of injection, vaccines containing adjuvants, specifically those containing aluminum, cause a more severe inflammatory response. Though rare, these severe reactions spread fear and doubt amongst cat owners concerning the safety and necessity of vaccines. It falls on the veterinary staff to fight these fears and doubts with facts and preventative measures. It is easy to lose sight of the dangers of a disease which, thanks to strong population immunity, is rarely seen. It is important that owners understand the benefits of vaccinations and the true risks of withholding vaccination from their pet. When fewer individuals in a population receive vaccines, the disease which was rare before may emerge again, causing suffering and death. The few risks associated with vaccinations can be avoided, if not entirely then at least in part. For example the ‘vaccine load’ on each individual animal can be decreased by individual risk assessment. In Sweden vaccinations are routinely given in the interscapular region as the incidence of fibrosarcomas are very low. If they were to become more common a change in routines may be in order as fibrosarcomas in that area are incredibly difficult to treat. Instead routines suggested by the World Small Animal Veterinary Association (WSAVA) could be implemented. These state that vaccines should be administered in the lateral abdomen region to facilitate excision of sarcomas. Also, non-adjuvanted vaccines should be chosen for cats when possible to further reduce risks of FISS developing. These changes in routines would not be able to eliminate the occurrence of adverse events but may serve to reduce the risk of the individual patient and improve the prognosis of individuals developing fibrosarcomas.