Vaccines for Cats: What You Need to Know


There is no question that vaccines protect against disease, but they also present considerable risk. Far too many cats are still being over-vaccinated because too cat guardians, still think annual “shots” are necessary, and sadly, far too many veterinarians still recommend them. This is a complex issue, and it’s up to cat guardians to educate themselves so they can make the best decision for their feline family members.

Which vaccines should your cat get?

The American Association of Feline Practitioners (AAFP) recently updated its vaccination guidelines. The guidelines divide vaccines into core and non-core vaccines, and recommended that vaccination protocols should be tailored to the individual cat’s health and lifestyle.

There are no easy, yes or no answers when it comes to which vaccines your cat should get. It depends on your cat’s age, health status, and lifestyle. It also requires weighing the benefits of vaccines against the risks. Two feline veterinarians who I trust completely have written outstanding articles on this topic, and I urge you to read both articles.

Feline veterinarian Fern Crist, DVM, provides a comprehensive overview of the available feline vaccines, and which ones your cat needs in Feline Vaccinations: Walking Through the Minefield.

Lisa Pierson, DVM, the founder of, addresses key issues associated with vaccines in Vaccines for Cats: We Need to Stop Overvaccinating.

Vaccine risks

Vaccines are implicated in triggering various immune-mediated and other chronic disorders. This is also referred to as vaccinosis. Vaccines are also implicated in the high incidence of vaccine-induced sarcomas in cats.

Dr. Karen Becker provides a detailed explanation of vaccinosis in her article Dog and Cat Vaccines are not Harmless Preventive Medicine.

Vaccines are also implicated in injection-site sarcomas. These tumors of the connective tissues are often called fibrosarcomas, and are most frequently located between the shoulder blades, in the hip region, and in the back legs. They are most often associated with inactive killed rabies or feline leukemia vaccines, or with multiple vaccines given at the same time, but they can also be caused by other injections such as steroids. The incidence of these tumors ranges from 1 in 1000 to 1 in 10,000 cats. They can develop as quickly as 4 weeks or as late as 10 years post vaccination.

Always demand non-adjuvanted vaccines for cats

Adjuvants are substances that are added to vaccines to alert the immune system that an antigen is present. They increase the immune response. Unfortunately, these adjuvants are also implicated in causing injection site sarcomas. Do not assume that your vet is using non-adjuvanted vaccines – ask before you allow any vaccine to be given to your cat.

Should you vaccinate your adult cat against distemper?

There is some compelling evidence coming from a study conducted at The Center for Companion Animal Studies at Colorado State University that shows that the common FVRCP (feline viral rhinotracheitis, calicivirus and paneleukopenia) vaccine may cause long-term damage to cats’ kidneys that increases with every booster. Click here for more information on whether you should have your cat’s distemper vaccine boostered every three years.

Vaccine titers as an alternative to over-vaccinating

Titer testing for a particular infectious agent measures the presence and level of antibodies in an animal’s blood. These antibodies reflect the combination of any natural exposure and vaccination and were created when the animal’s immune system responded to the antigens introduced into his body. The presence of a measurable serum antibody titer indicates the presence of “immune memory”, and signifies protection from disease.

For more information on vaccine titers, please read Dr. Jean Dodd’s article Let’s Talk Titers: Avoid Over-Vaccinating Your Cat.

Rabies vaccine: it’s the law

Almost all municipalities in the United States require rabies vaccinations for all cats, regardless of whether they’re indoor or outdoor cats. I’m not aware of any municipalities that accept rabies titers in lieu of a vaccine. The required frequency of rabies vaccines is set by local jurisdictions, and doesn’t appear to have much to do with the actual immunity duration of the vaccine. The Rabies Challenge Fund is hoping to change this by determining the true duration of immunity conveyed by rabies vaccines.

In order to minimize the risk that comes with each rabies vaccine while still complying with local laws, make sure that your veterinarian only uses the non-adjuvanted Purevax vaccine manufactured by Merial. This vaccine is the only non-adjuvanted rabies vaccine on the market, and comes in a 1-year and 3-year version. If your veterinarian doesn’t carry this vaccine, insist that they order it, or find a vet who does use it.

Before you agree to have your cat vaccinated, educate yourself about all aspects of this issue, and make an informed decision.

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