Adjuvanted and Non Adjuvanted Vaccinations – Why should my cat be concerned?

September 04, 2014 / Cat's Meow / Leave a comment

Cats are a species that are unique in many ways. One of the more sinister of these is their tendency to develop injection site reactions. What this means is that when given certain types of injections, cats may react at the site of the injection, the type of injection that is most risky for your cat is an “adjuvanted vaccine”. This is a type of vaccine that contains an “adjuvant” or irritating chemical along with the virus or bacteria. These adjuvants are essential for some types of vaccine in order to boost the immune response and ensure protection. In humans, dogs, and other species they are quite safe and effective. In cats however, they have been implicated in causing “Vaccine Site Sarcoma” (VSS) a malignant and often fatal cancer. The risk of this occurring is extremely low, estimated between 1 in 10 000 to 1 in 30 000 cats. The most commonly implicated vaccine is “Killed” or “Adjuvanted” rabies, however some other types of injection (such as some long acting drugs) have also been found to cause these reactions.


The risk of VSS is almost completely eliminated by the use of “Non-Adjvuanted Vaccines”. These vaccinations are specially formulated to eliminate the need for an adjuvant and allow for safe inoculation with little to no risk of tumor formation and are just as effective as their Adjuvanted counterparts.


Here at the Cat Clinic, we are proud to use ONLY non-adjuvanted vaccines in all our patients. We also avoid the use of any other drugs known to cause injection site reactions. Though these vaccinations are  more expensive than the adjuvanted versions, we strongly believe in providing only the best quality of care for our patients. 


Come talk to our knowledgeable staff and doctors at any time with questions or concerns you may have about vaccines in cats.

Written by Dr.Matthew Kornya

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