Are Booster Vaccines Necessary for Cats?

By Malcolm Weir, DVM, MSc, MPH; Rania Gollakner, BS DVM; Cheryl Yuill, DVM, MSc, CVH

Primary vaccination is essential to prevent the return of once common deadly infectious diseases in kittens and cats. Recent research indicates that not all vaccines require yearly boosters. However, there is no evidence that annual booster vaccination is anything but beneficial to most cats. Published research has conclusively shown that abstaining from some boosters can put your cat at risk.

Blood tests to measure the amount of antibodies (antibody titers) are sometimes recommended to establish whether boosters are necessary for your cat. Unfortunately, these tests are often more expensive than re-vaccination and may be stressful for your cat. In addition, just because your cat has a high serum antibody does not mean that these antibodies will ensure adequate disease protection should your cat be exposed to a virulent strain of disease.

"Through vigilance and high standards, the veterinary vaccines used today are safer and more protective than ever."

Government regulatory bodies have strict guidelines for vaccines, and manufacturers must prove that a vaccine is safe and effective before it can be used. Through vigilance and high standards, the veterinary vaccines used today are safer and more protective than ever.

I prefer my cat to have boosters only when necessary – is this okay?

It is possible, but to determine when boosters might be necessary for an individual cat, it is necessary to test the cat's blood to determine the antibody titers or actual level of immunity against each disease. If a specific antibody titer is low, your cat will require a booster vaccine. Currently, few monovalent vaccines (protecting only against one disease) are available; when they are available, they are likely to cost as much, if not more, than a multivalent vaccine (protects against multiple diseases). From your cat’s point of view, receiving one injection against the common diseases is preferable to a series of single disease vaccinations.

Most adult cats that received the complete booster series of vaccines as kittens should be revaccinated one year later and then every one to three years based on a lifestyle risk assessment. Currently, the Feline Veterinary Medical Association (FelineVMA) vaccination guidelines recommend that low-risk adult cats who receive the complete booster series of vaccines as kittens, and again one year later, can be vaccinated every three years thereafter for the core vaccines (feline viral rhinotracheitis, feline calicivirus, feline panleukopenia, and rabies).

Feline leukemia (FeLV) is considered a core vaccination for kittens, but whether to continue FeLV vaccination in adult cats depends on the cat's lifestyle and risk factors. Your veterinarian will determine if your cat needs boosters for non-core vaccinations (i.e., Bordetella, Chlamydia) at your cat’s annual check-up.

A cat who is strictly indoors and lives in an apartment building would be a reasonable candidate for less frequent vaccinations. In contrast, a cat who goes outdoors or is in frequent contact with other cats would be considered high-risk and should be vaccinated more frequently.

"...a cat who goes outdoors or is in frequent contact with other cats would be considered high-risk and should be vaccinated more frequently."

Some vaccine manufacturers have developed approved three-year vaccines for many of the core antigens; these vaccines are not available in all countries. It is important to note that administering a vaccine labeled for annual administration at a different interval, such as every three years, is an off-label use and may violate government regulations. Before adjusting your cat's vaccination booster schedule, it is essential to discuss your cat's lifestyle with your veterinarian and determine the appropriate vaccine program for your cat.

Are there any other advantages of annual vaccination?

Not all vaccines provide protection for a year, particularly those that protect against non-viral diseases, such as Chlamydia and Bordetella, that provide immunity for less than a year. Annual revaccination against feline leukemia is also recommended for cats who go outdoors or are exposed to other cats regularly. You and your veterinarian should decide which vaccinations your cat receives annually based on your cat’s lifestyle, age, and health status.

Before vaccine administration, your veterinarian will perform a health examination. You will be asked questions about your cat's health status, and the veterinarian will check your cat's head, neck, chest, abdomen, muscles, skin, joints, and lymph nodes. Annual vaccines mean annual examination by a veterinarian; veterinarians frequently detect infections of the teeth or ears and subclinical diseases (diseases that do not present definite or observable symptoms) such as underlying heart conditions, metabolic problems, or organ dysfunction during these visits. Early diagnosis allows more effective and successful treatment and may improve the quality of your cat’s life.

Cats age at a more rapid rate than humans do. Therefore, it is essential to ensure that they receive a complete physical examination on at least an annual basis. As they approach their mature and senior years, they should be seen twice yearly or as your veterinarian recommends. Cats 7–10 years of age are considered mature, and cats over 11 are senior.

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