There is a lot of controversy about vaccinations for dogs. Questions of which ones to give, why to avoid them, why to give them, how long they last, what exactly they do to the body/the immune system, and I’m sure, a million other permutations on this tricky subject have been asked.
I will begin with a disclaimer. There are research papers available on vaccinations and blood titers that can both confirm and deny much of what is said about this subject, and there is very limited consensus among veterinarians as to the best course for every dog. I do not profess to be an expert on this subject, but I can present some food for thought.
I practice both regular medicine and alternative medicine, and believe in the judicious use of vaccines, which have provided people and animals with immunity to many deadly diseases. They can themselves, however, cause health problems. Veterinarians and owners should consider the risk-to-benefit ratio for each vaccine they give their animals. For example, veterinarians will not vaccinate a dog if she is too young, sick, prone to severe vaccine reactions, suffering from immune-mediated diseases, or not exposed to the disease in question. Some veterinarians will give vaccines individually, separated by ten days or so between injections, to decrease the chance of vaccine reaction and to be able to determine which vaccine caused a reaction if there is one. With all of this in mind, I prefer to minimize vaccination where possible and prudent.
There are certain basic (core) vaccines that either are required by law or are sensible, based on area and exposure (see sidebar for a list of the three categories of vaccines). I recommend a three-year rabies vaccine for all my patients over one year old, and I may discuss with owners of very geriatric animals the option of signing a waiver to decline the rabies vaccination, depending on the animal’s health status. There are titer tests for rabies, but they are not routinely used except for animals traveling out of the country.
Knowing the duration of immunity (DOI) for a given vaccine is an important part of this equation, and is why vaccine titers were developed in the first place. Vaccine titers measure the concentration of an antibody to a specific disease present in the bloodstream. While it is not a perfect test, it is useful in helping us determine if—and for how long—an animal’s immunity to a disease lasts. Whether or not there is truly a direct correlation between the titer value and real immunity is not thoroughly understood, but the science so far seems to support the theory.
Studies have shown that animals given distemper and parvo vaccines maintained antibody titers for anywhere between four and seven years (or more) post-vaccination. Other tests have demonstrated that these animals remained healthy when challenged with a live virus, while unvaccinated animals contracted the disease. With this information, the veterinary profession then considered whether to vaccinate and how often. In 2006, the American Animal Hospital Association came out with new guidelines in which the recommended frequency of a number of vaccines (especially the distemper/parvo combination) has been decreased. It also lists several vaccines that it doesn’t recommend, and why (e.g., Corona, giardia, and leptospirosis, except where exposure is high). This 28-page document is available on their website.
Every animal has a different immune system, which is challenged by different virus exposures, stressors, lifestyles and diseases. Because of the wide range in tested immunity, veterinarians are more frequently recommending vaccine titer blood tests (which are now readily available) starting three years after the last distemper combination vaccine. These tests can also be used for young dogs after they have been given their initial series to be certain that they have retained immunity.