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.
The current vaccination recommendation for puppies is to start between six and eight weeks of age and then vaccinate every three to four weeks, with the last vaccine given at 12 weeks or older, where possible, limiting the number of vaccines within those guidelines. Veterinarians, breeders, owners, pet stores and shelters may have their own guidelines based on the puppy’s exposure to disease. Many veterinarians recommend a booster one year after the initial series just to be sure, but then move to the three-year interval for titer testing or vaccination if needed. I have found that a majority of the animals that I test have antibodies years after just their initial puppy series, but I use the titer to confirm it. Even though I may not have vaccinated very geriatric animals for many years, almost all of those I test retain good antibody titers well past the three-year mark.
The distemper/parvo vaccine titer/blood test costs more in dollars than the vaccination, but it decreases a cost to the animal’s immune system that can affect her health and longevity. There are possible connections with the onset of immune-related diseases, which, though anecdotal, still causes vets to avoid vaccinating animals with these problems. Adverse reactions also occur, most within 24 hours, and if treated with Benedryl or a steroidal anti-inflammatory, they resolve well. There is still much to learn about what effects vaccines have on the body.
The main thing I feel it is essential to remember is that each animal should be evaluated carefully, comparing the proposed vaccine with their age, breed (Greyhounds, for example, are particularly sensitive to many drugs), health status, environment, lifestyle, and travel habits. Most health professionals agree that minimizing vaccinations and using them prudently is a valuable goal—it is possible that we have been over-vaccinating animals, and titer testing now provides us with a tool to determine the true need.