Which vaccines does your cat really need?

Years ago, veterinarians gave every shot to every cat, every year. No one asked about lifestyle. No one asked if this was actually helping the cat or harming the cat. No one asked if one shot was different from the next.

Over the past 15 or so years, things have changed for the better! We’ve learned a LOT about vaccines, and have improved them greatly! The good news – we’ve learned that the immunity (the body’s protection against disease) lasts much longer than 1 year. The bad news – a very small percentage of cats can develop a specific kind of cancer (actually called vaccine-related sarcoma) that we think may be related to a component of vaccines.

Yes, vaccines save lives by preventing horrible and fatal diseases (like feline distemper, AKA panleukopenia). They may cause a fatal cancer in a very very tiny percentage of cats. We can’t let the pendulum swing the other way to “no vaccines ever.” We need to use them and be smart about it.dog and cat vaccines

The AVMA (American Veterinary Medical Association) and AAHA (American Animal Hospital Association)  and the AAFP (American Association of Feline Practitioners) researched and debated this issue for years. They agreed on recommendations of vaccines that are considered “core” and “non-core.” The core vaccines are recommended for all animals, and may be even required by law. Non-core vaccines are needed for some patients, but not all, as determined by that pet’s lifestyle, health status, and potential risk.

They also took another step and even have vaccines that are not recommended. Ever. Oh snap.


Core vaccines for cats:


This vaccine is required by law in all 50 states. Since 2012, all 50 states now also recognize the 3-year as well as the 1-year shot. Because rabies is a zoonotic and fatal disease (meaning people can get it – then die) law requires the vaccine must be given by a veterinarian, to prevent any shenanigans . Fortunately, the rabies vaccine is very well tolerated in pets. I recommend keeping all pets current on this vaccine (every 3 years isn’t so bad). Why? Well, it’s the law (Am I going to tell you to break the law? Um, no!). Also, while the chances of your cat actually contracting rabies are slim, we have identified rabies in stray cats and kittens from time to time. So it is out there.

The most important reason to keep your cat current on the rabies vaccine: your pet needs the paper trail. All it takes is one person to accuse your pet of biting them. A bite does not even need to happen! Depending on your local animal control, they can make life really un-fun, or be reasonable. If your pet is current on their rabies vaccine, you show that proof, keep your pet at home for 10 days, then go see a vet on day 10 who signs a form that your pet is non-rabid. Not a huge deal. Sure beats fines and quarantines!

FVRCP  or “Distemper combination”  (Feline Herpesvirus 1, Feline Calicivirus and Feline Panleukopenia Virus)

Yes, that’s a mouthful. FVRCP actually stands for Feline Viral Rhinotracheitis, Calicivirus, Panleukopenia. The most deadly of these three diseases is Feline Panleukopenia, AKA, Feline distemper. Just to be as confusing as possible, the cat version of distemper is nothing like the dog version. Cat distemper is actually very similar to the parvo virus that dogs get. Why they don’t call it feline parvo is beyond me – I just work here.

The other two viruses in this combo, Herpes and Calici, both cause upper respiratory infection (URI) in cats. These most commonly infect young kittens who are not yet vaccinated, and whose immune systems aren’t quite up to snuff. The sucky thing about herpes is that it can linger under the radar in a cat. Forever. Some cats experience flare-ups of the virus later in life, which look like milder forms of the original “head cold” they had as kittens. (Here’s a whole article on herpes in cats). The mast majority of cats in this country (85-90%, depending on who you read) have herpes in their systems.

Calicivirus (pronounced ka-LEE-see) is a frustrating one. About 10 years ago, a new strain came out that was very aggressive, not prevented by the vaccine, and more deadly than the “old” calicivirus. The original emergence seems to have settled down, but other strains are out there. This means the vaccine against calici is not super effective like it used to be. It is still considered a core vaccine, just because calici is pretty bad news. The newer strain causes very painful ulcerations on the tongue and mouth, making it difficult to eat or take medication. Best just to avoid it.

cat outside in grass

Non-core vaccines:

Feline Leukemia Virus

This virus causes leukemia and general immune system deficiency associated with that. There is no treatment for it, and it is always fatal eventually. Good news is that it’s a wimpy virus when it’s outside of a cat’s body, so it doesn’t live on  surfaces, beds, etc. For a cat to spread leukemia to another cat, they have to be pretty cozy with each other, and exchange saliva. This is usually done through grooming each other. If your cat does not go outside, he does not need this vaccine. If your cat goes outside and sits next to you on the porch, you can skip this shot. However, if your cat is roaming the neighborhood, mingling with other cats, then this would be a good shot to get.

Feline Immunodeficiency Virus (FIV, “Feline AIDS”)

For a cat to transmit FIV to another cat, they have to be even more intimate than for leukemia. Think of HIV transmission in people – you won’t get it through casual contact. You have to exchange bodily fluids, like via intercourse, blood transfusions, shared drug needles, etc. If your cat never goes outside, or goes outside under supervision, you do not need this vaccine. (Maybe educate your cat about not sharing drug needles with his shady kitty friends?). Seriously though, FIV is spread via intercourse and, most commonly, fighting and biting (blood and saliva mixing). The FIV vaccine is generally not recommended for any cats, even those that go outside. The vaccine can cause your cat (in theory) to test positive for the disease later in life.  To boot, it’s not all that effective in preventing disease transmission anyway. I don’t know very many vets who even stock it in their clinics.

Feline Chlamydia felis

This vaccine is not all that effective, has a higher rate of reactions, and the disease it’s meant to prevent is pretty easy to treat. I don’t know any vets who even stock this vaccine, but wanted to acknowledge its existence.

Feline Bordetella bronchiseptica

Bordatella? Isn’t that a dog shot against kennel cough? Yes, it is! They make a shot for cats as well (and it’s usually the squirt-up-the-nose form). Unless you have a lot of cats and kittens living in questionable conditions and have this respiratory disease going around, skip it. Again, I don’t know any vets who even stock this vaccine, but wanted to acknowledge its existence.

Not recommended

I would personally list the preceeding three vaccines under this heading as well, but the AAFP considers them options for a small subset of patients. They do not recommend the FIP vaccine at all, though. FIP stands for Feline Infectious Peritonitis, which is caused by a coronavirus (very different from the dog coronoavirus).  FIP is a very frustrating and poorly-understood disease still. The vast majority of cats in this country have been exposed to coronavirus, yet only a tiny minority develop FIP. It is usually in kittens, although I have seen adult cats with it as well. It is always fatal. Research is ongoing, trying to understand what makes some cats’ coronavirus turn into FIP, while the vast majority do not.

A note on adjuvants

So, that’s all you need to know about cat vaccines, right? I wish! With cats, there is an additional factor at play – adjuvants. These are added to certain vaccines to help wake up the immune system so it notices the shot. Once the immune system is all riled up about the shot, it creates the antibodies that are so important in protecting the cat from the disease. Several years ago, we realized that adjuvants may play a role in promoting vaccine-associated sarcomas in cats. The Leukemia vaccine was most often linked to this rare but very nasty cancer. Nowadays, there are vaccines without adjuvants made by a couple manufacturers. Most vets stock these and only these, but some places still stock the adjuvanted brands. So if your cat is needing vaccines, particularly leukemia, worth talking to your vet.

Posted in Feline specific, General health, Vaccines.

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