March 30, 2005


The tragic death of a young dog shortly after receiving routine vaccinations has sparked an animated exchange of opinions on an agility mailing list. I've been doing some reading ...

The Vaccine Controversy rages on two fronts. The first point to consider is the safety issue. Vaccines can be harmful. We vaccinate because the advantages outweigh the risks. Just ask anyone who has seen a beloved pet die of parvo or distemper. But there are risks associated with vaccinations. For instance some dogs, after being vaccinated with modified live canine distemper vaccine can develop seizures, a lack of coordination and other neurological dysfunctions caused from a rare condition called postvaccinal canine distemper virus encephalitis. Another problem noted with genetically susceptible animals is that it is possible for vaccinations to trigger various autoimmune diseases.

Another source of controversy is the recommended frequency of vaccinations. Although yearly boosters are recommended by most vets, for many diseases the yearly booster really is not obligatory. However, a yearly checkup is necessary for the same reasons you would have one yourself. For the low-risk pet, once the initial puppy series is completed, a booster at one year and another at three years should suffice until your dog's senior years. Unfortunately, no duration of efficacy studies are available yet because minimum duration studies were not required for vaccine licensure until recently. This means there really are no data that tell us how long the immunity lasts in a vaccinated animal, but animal vaccines should compare favorably with the duration of human vaccines. On the other hand, no data supports yearly vaccinations either.

The AVMA vaccine guidelines for dogs and cats released in November 2002 by the AVMA Council on Biologic and Therapeutic Agents recommend tailoring vaccine programs. The "COBTA Report on Cat and Dog Vaccines" concluded that inadequate data exist to scientifically determine a single, one-size-fits-all protocol for vaccination or revaccination of dogs and cats. It said that variations among patients, their lifestyles, and related disease risks, and between individual vaccine products available, necessitate a customized approach to vaccination recommendations. COBTA concluded that evidence shows that some vaccines provide immunity beyond one year. While annual vaccinations have been highly successful in curbing disease, the one-year revaccination frequency recommendation found on many vaccine labels is based on historical precedent, not scientific data. Even in cases where scientific data were submitted to qualify a label claim, the data generated generally represent a minimum duration of immunity and don't resolve the question about average or maximum duration of immunity.

The incentive for reducing vaccination is that various reports show serious immune system suppression in significant numbers of pet animals and humans resulting from routine annual or regular vaccination.

Vaccines can be separated into 'core' and 'non-core'. Some vaccines have had a profound effect by reducing, or eliminating, diseases characterized by moderate to high morbidity and/or mortality. However, other vaccines have had little or no recognized beneficial effect because they were designed to prevent infections that cause little or no morbidity and/or mortality. Some vaccines are so new that the potential benefits they provide are not known e.g., Giardia, Leptospira (L.) grippotyphosa and L. pomona.

A vaccine titer is a blood test that measures the antibody level a dog is carrying against a certain virus. There is a great deal of debate regarding whether or not a certain level of antibody can be considered tantamount to protection. Many veterinarians do not feel it is useful to run titers until this issue is resolved (ie there is more to protection than an antibody level; there is an entire immune system involved and there is no simple way to assess the entire immune system). Other veterinarians find it cost ineffective to recommend titers prior to vaccination (it costs a great deal more to run the titer than to simply give the vaccination. If the titer is adequate, the worst possible outcome is that the vaccine will be ineffective.) Other veterinarians question whether or not it is harmless to annually give vaccinations when there is already adequate immunity present.

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