Why Does My Indoor Cat Need Yearly Vaccinations?

Q: Do I need to take my indoor cats to get their yearly vaccinations? If yes, I wonder why, since they don't go out anywhere. What if I decide not to give them any vaccination? What will happen? I haven't vaccinated them for two years. Thank you.
 
A: For many years, it had been recommended that cats receive routine vaccinations on an annual basis. Rabies has been the exception; some rabies vaccines are labeled for annual vaccination, while other types of rabies vaccines have been shown to confer immunity for three years.  
The discovery that certain vaccines (the feline leukemia virus vaccine and the rabies vaccine in particular) have the potential to induce the formation of malignant tumors at the vaccination site has prompted a closer look at vaccination and whether annual vaccination may be unnecessary. We now know that the immunity to the common cat diseases that we vaccinate against (panleukopenia, feline herpesvirus, feline calicivirus) is fairly long-lived, at least three years, and that annual vaccination may be excessive and unnecessary.

If your cats have been properly vaccinated as kittens and you were keeping up with the booster vaccinations, then you probably don’t need to vaccinate until three years after the last panleukopenia-herpes-calicivirus vaccine. The reason why we vaccinate against these viruses, even though your cat is strictly indoors, is that your cat is very likely already infected with the feline herpesvirus. Most cats are exposed to this virus as kittens, and once they recover from their infection, they remain carriers for life. During times of stress, the herpesvirus can emerge from its dormant state, and cause signs of illness. If your cat is well-vaccinated, the clinical signs tend to be mild.

If your cat is unvaccinated or poorly vaccinated, he can get quite sick, depending on how the virus chooses to manifest itself. The panleukopenia-herpes-calicivirus vaccine is considered to be a “core” vaccine.  All cats should be vaccinated against it, and the vaccine should remain current. Rabies vaccination is also a core vaccine, and is required by law. I recommend staying current on your rabies vaccination.