Dr. Schultz is the leading canine vaccine researcher in the world. He has done more research on canine parvo vaccines than anyone else, and in fact on all canine viral gastroenteritis and vaccines for those viruses. He is the Chair of the Department of Pathobiology at the University of Wisconsin-Madison School of Veterinary Medicine, and was the editor of the text book "Advances in Veterinary Medicine: Veterinary Vaccines and Diagnostics."

The gist of current thought is this:

The reason we usually repeat vaccinations for parvo and distemper is not because we need vaccines more than once to form immunity. They are repeated for two basic reasons only: Habit, and to catch those few individuals who for some reason don't respond to the first vaccination. Most people, including some vets, don't seem to be aware of this, and have the belief that there is some number of shots that must be given to create immunity. A single immunizing dose of a modified live virus vaccine… in other words, one vaccine that WORKS… will form long term, probably lifetime, immunity to parvo and distemper.

We don't need to keep repeating the vaccines to know if they worked, either. Although titers as a measure of ONGOING immunity aren't all that useful, as a measure of whether or not an animal formed immunity from a recent vaccination, they are extremely, highly reliable. ("Vaccines and Vaccinations: Issue for the 21st Century", Richard B. Ford and Ronald D. Schultz. Kirk's Current Veterinary Therapy XIII, 2000.) Since it takes 7-10 days for the immunity to form, if you test a titer 10 days after a parvo and/or distemper vaccine, you will KNOW if the puppy had an immunizing response. You don't need to guess. (Assuming the pup is old enough not to still have maternal antibodies.)

As to titers: A zero titer doesn't mean a previously vaccinated adult dog is no longer immune. That is because titers measure circulating antibody, and dogs (and humans!) don't need circulating antibody to be immune to something. Immunity comes from "memory cells," which we have no way to measure. It is the memory cells that tell the body to form the antibodies when a previously encountered virus re-infects the body. (Science 1999;286:1377-1381, 1381-1383. "Immune system's memory does not need reminders.") If the animal recently encountered the virus, their level of antibody might be quite high, but that doesn't mean they are more immune than an animal with a zero titer.

One of the most interesting things I have learned is that evidence is now showing that repeating vaccinations doesn't "boost" immunity at all. All our habits of making sure pregnant bitches are recently vaccinated so they will have lots of immunity to pass on, worrying about "fading" immunity in adult dogs, or whatever our concerns, are not based on scientific reality. Re-vaccinating an already-immune animal has little or no benefit; the previous immunity will act like maternal antibody and inactivate the vaccine, and immunity is not "boosted" at all. So you have all the risks of the vaccination, and no benefit. (Schultz, R.D. "Current and Future Canine and Feline Vaccination Programs." Vet Med 3: No. 3, 233-254, 1998.)

Here are some other notes and citations:

  1. From Kirk's Current Therapy XIII, published in 2000: "Vaccines and Vaccinations: Issue for the 21st Century", Richard B. Ford and Ronald D. Schultz.

    Annual Vacinations

    Companion animal vaccination guidelines are currently undergoing critical scrutiny by representatives from private practice, industry, and academia. Despite widespread recommendations for annual revaccination, information available today suggests that current vaccination practices in North America do not neccessarily correspond with the body of knowledge pertaining to duration of immunity from licensed vaccines. As a direct result, companion animal practitioners should expect significant changes in the current standard of practice pertaining to the administration of vaccines to dogs and cats.

    Among the most significant changes anticipated in the future will be the recommendation to discontinue routine administration of annual booster vacinations to adult dogs (distemper virus and parvovirus) and cats (panleukopenia, feline herpesvirus 1, and feline calicivirus). The incidence of canine distemper, canine parvovirus, canine adenovirus, and feline panleukopenia among vaccinated adults (>1 year of age) is virtually zero. The correlation among vaccination, the development of a "positive" antibody response, and protection from exposure to virulent virus is excellent. Furthermore, protection from exposure derived from immunization is sustained for periods as long as 5 or 6 years or more.

  2. These notes were taken by Betty Lewis, AHT, from a seminar she attended given by Dr. Schultz in August 2001.

    Core Vaccines are distemper, adenovirus, parvo and rabies. He says all dogs must have these.

    His protocol is to give a single vaccine (he recommends the 5-way with the lepto left out) at 12-14 weeks of age. Wait two weeks and run parvo and distemper titers. If the dog has an adequate titer measure at Cornell as 1:100 or higher, there is no need to repeat either the vaccination or the titer for the life of the dog. Rabies is given separately and has to be re-vaccinated by state law.

    **Giving multiple vaccinations does not boost immunity, and, in some cases may erode it.

    Even though he recommends that the titer level be 1:100, he does not recommend re-vaccination unless there's a really low titer. He says it probably won't improve immunity, though it may make you feel better.

    Principles of basic vaccine protocol include having breeders give vaccinations at home so puppies don't go to the vet's office (sources of infection).

    The rabies vaccine is the most reacto-genic, he said, so best to give it separately. Benedryl can be given prior to a rabies vaccine. It will "dampen" the reactive effect of the adjuvants, but won't interfere with the immune response.

    Giardia vaccine is not recommended and a side effect is granulomas at the site.

    Immunologic imprinting

    This refers to the fact that the immune system should be vaccinated only when it is ready and at its optimum. If you vaccinate an immature immune system or one not capable of responding fully for any reason, and you get only a partial response, re-vaccinating will never give a better response.

    There has not been a recorded case of canine infectious hepatitis in the US in the last 20 years .(CAV-2)

    "Of course vaccines can trigger neurological and endocrine diseases; didn't I say that there is an intimate relationship between the immune, neurological and endocrine systems?"

    By law the vaccine companies have to put 2-3 times the required dose into the vial.

    If a breeding dog can't develop a titer, it's not a good breeding prospect b/c it will pass on the poor immune system.

    The three species with the most tendency to auto-immunity are humans, dogs and inbred mice.

    He said that boosting a mother's vaccine prior to pregnancy will not increase the level of maternal immunity in the puppies. It is safer for the bitch to wait until after weaning to vaccinate.

  3. From the Journal of the American Veterinary Medical Association, vol. 207 Aug 15, 1995:

    "In the past, it was believed that annual vaccination would not hurt and would probably help most animals. However concerns about side effects have begun to change this attitude. One disadvantage to over-vaccinating is cost. The client is paying for something with no effect or with the potential for an adverse reaction. I believe that adverse effects are increasing because we are putting more and more components into these animals .......There is a real concern that vaccines may predispose certain genetically susceptible individuals to immune-mediated disease. The more antigens we administer, the higher the potential for hyper-sensitivity. Type 1 is IgE mediated; type 2 cytotoxic antibody mediated; type 3 immune-mediated, type 4 cellular mediated. All of these hypersensitivies are natural parts of the immune response, but they cause a certain amount of tissue damage. In many cases it is impossible to show a direct connection between damage and a vaccine, since it is the accumulation of many antigens over many years that results in clinically evident disease."

  4. Kirk's Current Veterinary Therapy XI, "Canine and Feline Vaccines," Phipps et al:

    "A practice that was started many years ago and that lacks scientific validity or verification is annual revaccinations. Almost without exception there is no immunologic requirement for annual revaccination. Immunity to viruses persists for years or for the life of the animal."

I posted these before, but these are good links to bookmark or share with your vet: