Why do indoor cats need rabies shots and other vaccinations for contagious diseases?

by Michael Broad · June 23, 2022

Clearly, a decreased contact with other cats is a powerful way of reducing the exposure of a cat to pathogens. And if a cat is kept indoors full-time under careful caregiving and they are the only cat in that home there is no contact with other animals from which they can contract a contagious disease. So why do they need rabies shots and other vaccinations for contagious diseases?

Snoozing comfortable cat indoors. Image by David Mark from Pixabay

Well, in the USA, with respect to rabies, cats have to have the rabies shot by law and therefore there is no need to argue about the practicalities of it. However, because rabies is such a disastrous disease, in the interest of an abundance of caution, cat owners have to arrange for a rabies jab just in case their cat escapes their home in some way or another.

And it applies just as much for a cat confined to a house as one on the twentieth floor of an apartment block. Although it is highly unlikely, almost impossible to envisage a cat escaping a flat on the twentieth floor of a condominium and surviving to contract and then transmit the disease to others, it is possible in extreme circumstances.

It is also possible for a cat owner to take their perfectly healthy, indoor cat, to a veterinarian in their car and in doing so their cat might escape. The cat will then have to make contact with another animal either wild or domestic which has rabies and be bitten by that animal. That would be unlikely in the middle of suburbia but once again it is remotely possible.

Cat Vaccination. Photo: The Answer Vet

And once again because of a sensible policy of an abundance of caution, a vaccine against rabies is an obligatory legal requirement. Ethically there are different arguments as vaccines are about risk and reward, benefits and detriments. This is because there is a risk of injury at the vaccination site.

Other contagious diseases

There are other contagious diseases which are not fatal for which there are vaccines such as the cat flu. Indoor cats can still contract these diseases, not from another cat in the home because there are none but from their cat owner who has gone outside. An example would be the feline calicivirus (FCV) which is described as “hardy” and able to survive on surfaces for up to a month in certain environments. It is one of the main causes of cat colds with the herpes virus.

The owner of a full-time indoor cat, when they are outside, might handle an infected cat or touch a surface on which the virus is located. Perhaps they went into a veterinarian’s clinic to buy some cat food and the virus is present on the counter. That is highly unlikely but just about possible. As a consequence, he or she could bring the virus back into their home inadvertently and transmit it to their cat.

These are slim chances and it seems to me that to vaccinate a full-time indoor cat who is cared for carefully against a core disease such as feline calicivirus can only be justified out of an abundance of caution. But it is justified if you believe in that kind of caution.

That said, it is a balancing act because all vaccines carry a health warning even if it is modest. You have to balance the benefits of a vaccine against the detriments. Personally, I would think that in this instance you are getting very close to the point where a vaccine should not be given. Of course, veterinarians would disagree with me. Some people, however, are a bit anti-vaccine and they might object to vaccinating their indoor cat against diseases other than rabies.

From my perspective, another factor which reduces the likelihood of a cat contracting infectious disease when they go outside is the fact that if they live in an area where all the cat owners take their cats to a veterinarian for a full vaccine programme, the disease is suppressed in that area to the point where the chances of contracting it are very minimal.

Below are some more pages on cats and rabies.