Why does my kitten need so many shots? Does my cat need to be vaccinated every year? These common questions about vaccinations don’t necessarily have easy answers. Deciding what vaccines to get, when to get them, and how often to booster them depends on a number of different variables, including how safe and effective the vaccine is, what your cat’s chances of getting the disease is and how serious the disease is. In this article, we’ll offer some guidelines to help you make these decisions, but it is important to always check with your veterinarian since he or she knows your cat and circumstances the best.
The role of vaccines
Why do we vaccinate our cats in the first place? The main reason most people vaccinate their cat is to prevent that individual cat from getting a specific disease. The vaccine stimulates an immune response in your cat to a disease it is exposed to. Even if your cat never leaves the house, it is possible that you could bring a disease home on your shoes or clothing, or that your cat could accidentally get outside. Vaccination also protects the general population of cats, and, in the case of diseases that are spread to people (zoonotic diseases), may protect the human population as well. Although thousands of people die of rabies worldwide, human deaths due to the rabies virus are rare in the United States due to animal control and vaccine requirements for our pets.
Core vs. non-core vaccines
The American Association of Feline Practitioners (AAFP), a veterinary group devoted to the health and welfare of cats, has developed a set of guidelines for the vaccination of cats. Included in these guidelines are four “core” vaccines that they recommend for all cats in the United States, whether they go outside or not, based on the infectious nature of the disease, the severity of the disease, and the effectiveness and safety of the available vaccines. These core vaccines include rabies virus, feline herpesvirus-1 (also referred to as feline viral rhinotracheitis or FVR), feline panleukopenia (also referred to as feline distemper), and feline calicivirus. The FVR, calicivirus, and panleukopenia vaccines are commonly combined in a single shot known as the FVR-C-P vaccine. The rabies vaccination is always given separately.
Other common vaccines that are considered “non-core” include feline leukemia (FeLV), feline immunodeficiency virus (FIV), chlamydophila, and bordetella. Feline leukemia is often recommended for all kittens but is especially important for cats that go outdoors or share their households with infected cats. Cats that are in catteries, spend time at kennels, or travel to cat shows may be more at risk for some of these diseases as well. It is important to discuss your cat’s lifestyle with your veterinarian when determining which vaccines your cat should receive.
Testing before vaccination
Kittens and cats can be infected with some of these diseases without showing any signs when young. They can be infected with feline leukemia virus (FeLV) or feline immunodeficiency virus (FIV) from their mother at birth. Because it is important to know this for future care, all cats should be tested for FeLV and FIV before vaccination. The FIV vaccination is generally only recommended in cases of high risk (e.g., living in a household or neighborhood with FIV positive cats), as current vaccines cause cats to test positive for the disease even when they are not infected.
Timing of vaccines for kittens
Most vaccines require a series of shots when a kitten is young, starting at 6 to 8 weeks of age. When the kitten is a newborn, it gains passive immunity against diseases from its mother in the first milk, or colostrum. If the kitten is first vaccinated when these antibodies are at a high level, the vaccine will not be effective, but if the kitten isn’t vaccinated and the maternal antibody level falls, then the kitten will be unprotected. Because the antibodies disappear at a different rate in every cat, a series of several vaccines (for most diseases) are given 3 to 4 weeks apart until the kitten reaches 12 to 16 weeks of age. It is then important for the cat to receive another vaccine against the disease a year later. Because kittens are more prone to vaccine reactions than adult cats, some veterinarians administer the vaccines separately so that the kitten doesn’t receive more than one to two shots at a time. A single rabies vaccine is administered at 12 to 16 weeks and then boostered one year later.
Timing of vaccines for adult cats
If an adult cat has never been vaccinated before, or has an unknown vaccination history, then a series of two shots, 3 to 4 weeks apart, is generally recommended for most diseases. Once the initial vaccine series has been completed for the adult or kitten, the core vaccines usually need to be boostered every 3 years. This is a change from previous recommendations when it was thought that vaccines needed to be boostered on an annual basis. Recent research has shown that this usually isn’t required and that the immunity from the vaccine will last several years. Many of the “noncore” vaccines, such as FeLV and Bordetella, still require yearly boosters, so it is important to follow the manufacturer’s guidelines on all vaccines and speak to your veterinarian about what he or she recommends. It is also important to have your pet examined every year by a veterinarian to be sure your pet is healthy and to ask any questions you might have.
While most vaccines are very safe, there are times when your cat can still become infected with a disease or may have a reaction to the disease itself. Vaccine failure can occur due to manufacturing problems (very rare due to the safeguards built into the process) or due to handling failures before it is given (more common). Most vaccines need to be kept refrigerated and then mixed up properly before administration. Ordering vaccines over the Internet or getting them from another source increases the chance that handling errors might occur in transit. Some vaccines do not produce a very high immunity to the disease. Preventing exposure to the disease by keeping your cat indoors or otherwise limiting its interaction with unvaccinated cats is the most effective way to be sure it doesn’t become infected.
Another concern with vaccinations is the possibility of side effects. The point of vaccination is to induce an immune response in the cat, and vaccines are specifically designed to do this. Some individuals mount more of an immune response than necessary. This could result in a mild vaccine reaction, such as lethargy or running a slight fever the day of the vaccine, or a serious life-threatening allergic reaction. These reactions may be hard to predict, so it is important that you alert your veterinarian to any reactions your cat may have had to vaccines in the past. Vaccine-induced sarcomas are a serious cancer that rarely develops at the site of a vaccination in cats. They have been associated with a number of different vaccines, and research is being conducted to better understand why some cats develop them while most don’t.
Keep in mind that no vaccine is 100% effective against the disease it is supposed to prevent and no vaccine is 100% safe, but many vaccines are very safe and very effective and much less risky than the diseases themselves. The chance that your cat will have a reaction to a feline leukemia vaccine is much less than the chance that your cat may be infected if it goes outdoors and interacts with infected cats. It is important to balance out the risks versus the benefits in determining vaccination schedules for your pets.
Nancy Dreschel, D.V.M., Ph.D. – Pennsylvania State University
- Viral Diseases of Cats
For more information
AAFP 2006 Feline Vaccination guidelines, JAVMA, Vol. 229, No. 9, November 1, 2006.
Vaccinations – AVMA animal health brochure