How Vaccines Work: Vaccines stimulate the immune system to produce antibodies to a disease organism so that the dog is protected against various pathogens in its environment. If the immunized dog is later exposed to the infectious agent, these antibodies react quickly to attack and neutralize the disease

How Frequently To Immunize: In the January 2004 issue of a U.S. veterinary journal, an article was published by the Pfizer Drug Company, a major manufacturer of dog vaccines. They determined that their canine vaccines were active (protective) up to and beyond four years after administration for all five of these diseases (1). Other studies have documented immunity lasting up to seven years (2)(3). No two vaccine manufactures produce identical products so you should not assume that the brand your veterinarian uses induces this long immunity but I suspect they all protect well over a year.

There may be risks associated with too frequent vaccinations.

For one, the immune system of your pet is stressed by these vaccinations. Occasional dogs develop allergic reactions, facial edema, enteritis, lethargy, fevers, pruritis, nausea, coughing. We also suspect that vaccinations can trigger certain autoimmune diseases such as Adison’s disease on dogs. Occasionally these reactions are life threatening. Vaccines contain many ingredients besides the dried virus.

Some of these, antibiotics and adjuvants (enhancers) are implicated in vaccine reactions. When these vaccinations are given they are best given subcutaneously with a TB syringe with 25-gauge needle. This small needle is less likely to carry a plug of skin into the injection site causing swelling and inflammation. In dogs that have had prior history of vaccine reactions I often do not give yearly vaccinations. I feel the risks outweigh the benefits.

If I am suspicious that a dog might have a reaction to a particular vaccine I pre-administer antihistamines (Benadryl) and give a minute test dose of 0.05ml. If the dog is normal thirty minutes after the test dose I give it the remaining one-milliliter. I limit yearly or every two-year vaccinations for the four “core” diseases to “higher risk dogs”. Higher risk dogs are dogs that roam or take unsupervised strolls; dogs that play with other dogs not from their household, dogs that have contact with wild animals, or swim and drink from pools puddles and streams.

Other higher risk dogs are coprophagic (eat stool). Others are more at risk because the attend obedience classes, dog shows, field trials, and large grooming and boarding facilities. About half the dogs I see fall into this higher risk category.