Dear Doctor: Over-vaccinating?


Q. I recently read that the American Animal Hospital Association recommends vaccines not be given more frequently than every 3 years and that excessive vaccinations can aggravate autoimmune diseases. The veterinary hospital I visit with my dog recommends a distemper shot every year. Is there science to support the idea of vaccinating annually?

MaryAnn Burden

Lebanon, New Jersey

Dear Ms. Burden,

A. The latest thinking by the American Animal Hospital Association

(AAHA) is that once every 3 years is enough for a distemper booster as well as boosters of vaccines against parvovirus and adenovirus-2. These three together constitute the core vaccines for which all dogs are candidates. (Parvovirus attacks the gastrointestinal tract and the immune system, causing symptoms ranging from severe vomiting to diarrhea and sometimes, whole-body bacterial infections. Adenovirus type 2 causes the liver disease hepatitis as well as a respiratory infection.)

Not only does the AAHA recommend every 3 years for a distemper shot rather than once a year, the organization goes as far as to say that if a blood test indicates antibodies to the disease are high enough, you can wait even longer than 3 years. Many people choose not to order antibody titer tests and just go with once every 3 years, however, as the titer tests can be more expensive than the vaccines themselves — up to $150 as opposed to about $50.

As far as the idea that vaccinating can aggravate autoimmune illnesses, the AAHA says “it has been suggested that doing so could reactivate disease.” For that reason, it advises that “when feasible, avoid administering booster doses of vaccine to patients having a history of immune-mediated disease.” In certain cases you might have no choice, for instance, where periodic boosters against rabies is the law.

Bottom line: Once a year for a distemper shot overshoots the mark for dogs in general. However, yearly vaccines are unlikely to harm a dog, says Tufts veterinarian and Your Dog editorial advisory board member Elizabeth Rozanski, DVM. Importantly, she adds, a visit to the vet for a vaccine often includes an important yearly examination for early detection of medical problems. For a dog with an autoimmune disease, on the other hand, even once every three years may be too often. It’s something that should be worked out with a veterinarian on a dog-by-dog basis.


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