For cats (and dogs), there are what we call core & non-core vaccines. Core vaccines are those that all animals should receive, regardless of their lifestyle. In other words, even cats who are always indoors should receive the vaccines designated as the core for their species.
The first core vaccine for cats is Rabies, which is a potentially fatal viral disease. Indoor cats can be exposed to rabies through wildlife entering the home, particularly bats. All dogs and cats are required, by state law, to receive this vaccine. The only exception would be if the pet has a specific health condition where vaccines are contraindicated. In this instance, a veterinarian must submit a legal form exempting the pet from vaccination.
The other vaccine that is considered a “core” vaccine for indoor cats is the Feline “Distemper” complex which protects against three potentially fatal viruses: Feline Viral Rhinotracheitis, Calicivirus, and Panleukopenia. It is usually given as a combination vaccine – FVRCP – and sometimes has additional immunizations added in. While this vaccine is not required by law, it is considered a core vaccine for cats because of the communicability of the Distemper virus and the danger it poses to other cats.
We will save discussion of feline Non-Core vaccines for another “Ask The Vet” column. In the meantime, don’t forget that it is also extremely important, regardless of your cat’s vaccine needs, that your cat receives a physical exam by a veterinarian at least once a year.
Please remember, this answer is for general information only and is not meant to substitute the advice of your cat’s veterinarian.