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Vaccinations are the most important preventive measure you can take for the health of your pet. Health threats vary from city to city and even in various sections of cities. Therefore, your veterinarian can tailor an immunization program for your pet based on local conditions. Your dog or cat generally can be immunized for the following diseases: Dogs can be immunized against distemper, hepatitis, leptospirosis, parainfluenza, parvovirus, coronavirus, Bordetella, rabies, and Lyme disease. Cats can be immunized against feline panleukopenia (distemper), rabies, feline rhinotracheitis, calicivirus, chlamydia, feline leukemia, and FIP.

In recent years some veterinarians have changed their recommendations regarding the frequency of vaccinations. The following fact sheet provides answers to important questions concerning vaccinations.

Does My Pet Need Annual Vaccination? Questions About Vaccine… Which Ones and How Often?
Q: My whole life I have been told my pet needed yearly vaccinations. What has changed?
A: First you need to know that veterinarians have always acted in what they believed to be the best interest of pets and pet owners. Vaccines against infectious diseases have done much to reduce sickness and death in companion animals.

The tradition of annual boosters was based on manufacturers’ recommendations and labeling. To date, few studies have been done to prove how long vaccines are effective. In addition, veterinarians found vaccination to be a safe procedure that was generally free of side effects and risk.

Recently, there has been a growing degree of evidence indicating protection from vaccination is longer lasting than previously believed. In addition, there is increased awareness and concern that vaccination is not as harmless a procedure as once thought. This awareness and concern have led to a growing number of authorities (such as infectious disease experts, immunologists, and researchers) as well as practitioners who recommend reduced frequency of vaccinations while at the same time tailoring vaccine recommendations to specific risk situations.

Q: Is vaccinating my pet a risk to his or her health?
A: Vaccination against disease is a medical procedure and, like all medical procedures, carries some inherent risk. As in any medical procedure or decision, the advantages must be balanced against the risks. Veterinarians recommend that no needless risks should be taken and that the best way to accomplish that is to reduce the number and frequency of administration of unnecessary vaccines.

As is the case with any medical decision, you and your veterinarian should make vaccination decisions after considering your pet’s age, lifestyle, and potential exposure to infectious diseases.
Q: What possible risks are associated with vaccination?
A: Again, severe reactions are uncommon, but any needless risk is unacceptable. In general, vaccine reactions and side effects (such as local pain and swelling) are self-limiting. Allergic reactions are less common, but if untreated can be fatal.

In a small number of patients, vaccines can stimulate the patient’s immune system against his or her own tissues, resulting in diseases that affect the blood, the skin, the joints, or the nervous system. Again, such reactions are infrequent.

In a tiny percentage of cats, there has been an increase in a particular form of tumor that is strongly associated with vaccine administration. The reported incidence of this side effect is one in 10,000. Researchers are currently studying this phenomenon to learn what causes the problem so that vaccines can be redesigned to avoid this unacceptable side effect. Meanwhile, reducing risk by reducing the number of unnecessary vaccines given to cats is the safest option.

Q: How do I know which vaccines my pet needs?
A: There are two general groups of vaccines to consider: core-group vaccines and noncore vaccines. Core-group vaccines protect against diseases that are more serious or potentially fatal. These diseases are more easily transmitted than noncore diseases. Core group vaccines are those generally recommended for all pets. For cats, these include panleukopenia, calicivirus and herpesvirus, as well as rabies. For dogs, we include distemper, adenovirus, parvovirus and rabies.

Noncore-group vaccines are those reserved for patients at specific risk for infection due to exposure or lifestyle. For cats, these include feline leukemia virus, feline infectious peritonitis, feline pneumonitis, Microsporum canis, and Bordetella. For dogs, these include kennel cough, Lyme disease, leptospirosis, and giardia.

Q: How often should my pet be vaccinated?
A: It depends. There is some controversy over the length of time a vaccine is protective. Some vaccines may produce life-long protections. There is a history of yearly vaccinations boosters, and some veterinarians do not feel it is prudent to change that recommendation just yet. There is growing support for extended duration of protection and a growing number of veterinarians are vaccinating less frequently and more selectively.

Among those advocating for longer periods of time between vaccinations, the thought is that vaccination for most core diseases should be administered every three years. Noncore disease vaccinations should be administered whenever the risk of the disease is significant enough to override any risk of vaccination. For example, kennel cough vaccine may need to be administered up to every six months in a dog repeatedly being kenneled or exposed at dog shows.

Q: Does this mean I only need to see my veterinarian every three years?
A: Annual physical examinations are very important whether your pet is vaccinated annually or less frequently. The historic protocol of annual vaccination has long encouraged the more important annual physical examination. Given his or her shorter life span, a pet ages much more rapidly than a human does. In addition, a pet does not always show signs of early disease, nor can he or she easily communicate discomfort to us. Veterinarians can best detect and prevent problems such as heart disease, kidney and liver disease, dental disease, cancer, and parasites by examining a pet annually. In addition, questions about behavior, nutrition, and preventive care should be addressed on at least an annual basis.

One of the advantages of decreased vaccine administration is the reduced cost of basic health care. This may make it easier for you to collect baseline or yearly recommended blood tests, provide better nutrition, or provide for nonurgent care for your pet before the need becomes urgent.

Q: Is there some sort of test that can be done to determine if my pet needs vaccination?
A: In theory, this makes very good sense. Veterinarians could test animals yearly and vaccinate if their protection dropped below a certain level. Although there are tests for antibodies available for some diseases, their reliability is not good. There may be little correlation between the results of these tests and the immunity to disease in an individual pet. In addition, the cost of these tests may greatly outweigh their value. New tests may be developed in the future, so discuss this possibility with your veterinarian.
Q: I have been vaccinating my pets every year for their entire lives and have never had problem. Are you sure I should change my approach?
A: Not many things are “sure” in medicine. However, there is strong and growing consensus among immunology and infectious diseases experts that annual vaccination is neither necessary or advisable. The vast majority, if not all of the North American veterinary schools, are currently recommending reduced frequency of vaccination as well as using the core/noncore concept in recommending specific vaccines. However, vaccination administration should be tailored to meet the needs of each patient, and there may well be specific situations of risk based on local outbreaks or your pet’s lifestyle that warrant specific recommendations. If you are more comfortable with annual boosters or with immunizing against a specific disease, please discuss the issue with your veterinarian.