Feline Vaccines: Benefits and Risks

Deciding which vaccines your cat should receive requires that you have a complete understanding of the benefits and risks of the procedure. For this reason, it is extremely important that you discuss vaccination with your veterinarian so he or she can help you decide which vaccines are most appropriate. Be sure to inform your veterinarian of your cat's lifestyle, environment, medical history, current medical problems, and medications your cat may be receiving. Remember, your veterinarian is more than willing to answer any questions you may have and will help you make the right vaccine choices.

At Animal Care Hospital we recommend that cats under 7 years old that live indoors get a thorough physical examination annually as well as an FVRCP vaccination every 3 years and a Rabies vaccination annually. If your cat goes outdoors we recommend the same vaccinations as indoor cats as well as a Feline Leukemia vaccination and an oral deworming for intestinal parasites.  Cats over 7 years of age typically still follow the above vaccination schedule, but should be examined every 6 months to monitor age related changes.  As cats age and become more frail, it is a good idea to discuss the necessity of vaccinations with your veterinarian and make decisions on an individual basis.

Why does my cat need to be vaccinated?
The immune system plays a pivotal role in maintaining your cat's health. One of the most important functions of this complex system of specialized cells and molecules is to protect cats from disease and infection caused by viruses, bacteria, and a host of other microbes and parasites.

Vaccines help prepare your cat's immune system to fend off invasion by a particular disease-causing organism. Vaccines contain antigens, which to the immune system "look" like the organism but don't, ideally, cause disease. When a vaccine is administered, the immune system mounts a protective response. Then if your cat is subsequently exposed to the disease-causing organism, its immune system is prepared to either prevent infection or reduce the severity of disease.

Though vaccines play an important role in controlling infectious diseases, most do not induce complete protection from disease, nor do they induce the same degree of protection in all cats. For extra protection, you should make every effort to reduce your cat's exposure to infected cats or contaminated environments.

Why do kittens require a series of vaccinations?
During the first few hours after birth, kittens ingest maternal antibodies contained in their mother's milk. These antibodies help protect the kitten from infectious diseases until its own immune system is more mature.

Unfortunately, maternal antibody also interferes with a vaccine's ability to stimulate the kitten's immune system. To counteract this problem, veterinarians often administer a series of vaccines, usually beginning when the kitten is around six to eight weeks of age. Vaccination is then repeated at three- or four-week intervals until maternal antibody has waned, usually at around twelve weeks of age. In some cases (e.g., rabies vaccines) the initial vaccine is not given until maternal antibody has disappeared altogether.

Does my adult cat need to be vaccinated every year?
The answer depends in part on the vaccine. Recent research suggests that panleukopenia, rhinotracheitis, and calicivirus vaccines provide adequate protection for several years, so that many veterinarians are now recommending that this vaccine be boosted no more than once every three years.

Unfortunately, far less is known about the duration of protection provided by other vaccines. Until that information is known, annual vaccination with those products-when their administration is necessary-is a good idea.

Are vaccines dangerous?
Not usually. Unfortunately, a perfect, risk-free vaccine does not exist. Vaccines are indispensable in fighting feline infectious disease. But as with any medical procedure, there is a small chance that reactions may develop as a result of vaccination. To maximize the benefits of vaccination while minimizing the risks, it is important to vaccinate only against infectious agents to which your cat has a realistic risk of exposure, infection, and subsequent development of disease. Also, make sure to inform your veterinarian of any problems your cat is currently experiencing, medications your cat is receiving, or vaccine reactions experienced in the past before your cat is vaccinated again.

Reactions may be mild or (very rarely) severe.

Mild Reactions 
The following reactions are fairly common and usually start within hours to several days after vaccination. They typically last no more than a few days.

  • Discomfort at the site where the vaccine was given
  • Mild fever
  • Diminished appetite and activity
  • Sneezing about four to seven days after administration of an intranasal vaccine
  • Temporarily sore joints and lameness following calicivirus vaccination
  • Development of a small, firm, painless swelling under the skin at the site where the vaccine was given. The swelling usually goes away after several weeks, but if you notice such a swelling, contact your veterinarian.
  • Lameness, loss of appetite, and fever beginning approximately one to three weeks after Chlamydia psittaci vaccination.

Serious Reactions 
These reactions occur very rarely:

  • A serious and potentially life-threatening allergic reaction within several minutes to an hour after vaccination
  • A tumor called a sarcoma developing at the vaccine site several weeks, months, or even longer following vaccination

What should I do if I think my cat is having a reaction to a vaccine?
By all means, consult your veterinarian. Even though vaccine-related disease is uncommon, the consequences can be serious. Your veterinarian is the person most qualified to advise you if adverse side effects occur.

Which vaccines should my cat receive?

The decision depends on the following factors:

  • Your cat's risk of exposure to the disease-causing organism, in part dependent on the health of other cats to which yours is exposed, and the environment in which your cat lives.
  • The consequences of infection
  • The age and health of your cat
  • The protective ability of the vaccine
  • The frequency or severity of reactions associated with vaccination
  • The risk an infected cat poses to human health (e.g., rabies virus)
  • Vaccine reactions your cat may have experienced in the past

This brochure was prepared by the American Association of Feline Practitioners and the Cornell Feline Health Center, Cornell University, College of Veterinary Medicine, Ithaca, New York 14853-6401. The center is committed to improving the health of cats by developing methods to prevent or cure feline diseases and by providing continuing education to veterinarians and cat owners. Much of that work is made possible by the financial support of friends. ©2002 by Cornell University. All rights reserved. Cornell University is an equal opportunity, affirmative action educator and employer.


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