Monday, October 1, 2007

Vaccination Decisions

There are a couple of common sayings I hear frequently when mushers converse. The first is “Any time you get three dog mushers together to discuss an issue you’ll hear four different ideas, but no two people will agree on any one of them. This saying acknowledges that many topics are controversial. The second saying is often uttered in response to the first – “Everyone has to drive his (or her) own team.” In plain English, it means that when confronted with multiple options it is the individual musher’s responsibility to use his or her best judgment to make the decision that is most appropriate for his or her own dogs and individual circumstances.

These two sayings come to mind because I’m currently enmeshed in a discussion among several mushers about the most appropriate vaccination protocol for my team and for sled dog teams in general. I’m afraid I’m the one who initiated the discussion. I’m a new musher, and my team is due for their annual veterinary examination and vaccinations. At the end of day I will have to “drive my own team” by deciding which approach to vaccination is most appropriate for my dogs.

Until recently canine vaccination didn’t take a lot of thought. Most veterinarians recommend a “hit ‘em with everything once each year” approach, all but demanding that their clients to vaccinate against a laundry-list of diseases each and every year. Within just the past 3 years the major veterinary medicine associations have changed their recommendation considerably, advocating a more conservative approach based on the needs of individual animals.

There is no question that vaccines have had a huge impact on canine health and for literally saving the lives of millions of dogs over the past 50 years or so. In the late 1970s parvovirus was especially deadly, killing many thousands of dogs. The horrendous epidemic was halted by the mass vaccination of dogs. Just last month the United States Centers for Disease Control and Prevention announced the canine rabies (but not other forms) has been eradicated from the United States, a feat that could not have been accomplished without modern vaccines.

When it comes to keeping our dogs healthy, vaccines are the best thing to come down the pike since bottled beer, but like bottled beer it is possible to have too much of a good thing. During the 1990s the major veterinary associations were facing a growing body of scientific evidence showing the vaccines are not totally benign and that vaccinations may cause or contribute to a number of fairly nasty diseases. In dogs some of these diseases include anemia, arthritis, seizures, allergies, gastrointestinal problems, immune system problems, thyroid disorders, and cancer. Although the incidence of vaccine induced diseases are rare, that is scant comfort when it is YOUR dog that is afflicted.

In response to the evidence, the American Animal Hospital Association (AAHA) created a task that issued new guidelines for dog vaccination in 2003, and revised those guidelines in 2006. The AAHA guidelines took an evidence-based approach similar to that being used by human medical specialty associations. The AAHA guidelines were quickly accepted and promoted by the American Veterinary Medicine Association (AVMA), the Canadian Veterinary Medicine Association (CVMA) and the World Small Animal Veterinary Association (WSAVA).

Like evidence-based guidelines for human medical care, the canine vaccination guidelines categorizes vaccines. “Core” vaccines are those which are recommended for almost all animals, “noncore” (optional) vaccines are recommended for some animals based on individual factors, and “not recommended” vaccines. Core vaccines are those that scientists know are effective AND protect against the scariest of canine diseases. This include rabies, parvovirus, canine adenovirus and canine distemper.

The AAHA guidelines also provide a schedule for revaccination based on the known duration of immunity offered by the vaccines, most of which are much longer than the 1 year revaccination recommended by profit-driven manufacturers. All of the core vaccines and most of the noncore (optional) revaccinations are recommended on a three year schedule for most healthy adult dogs. Some of the noncore (optional) vaccines, including bordetella (kennel cough) still require annual revaccination to provide immunity.

Another option one might discuss with his or her vet is measuring antibodies in the dog’s blood serum and basing revaccination decisions on the results. The term “titer” refers to the strength or concentration of a substance in a solution. When testing vaccine titers in dogs, a veterinarian takes a blood sample from a dog and has the blood tested for the presence and strength of the dog’s immunological response to a viral disease. If the dog demonstrates satisfactory levels of vaccine titers, the dog is considered sufficiently immune to the disease and does not require further vaccination against the disease at that time. If the level of vaccine titers is too low, then dog may be revaccinated.

AAHA, AVMA, CVMA and WSAVA all apparently agree that for core vaccines there is excellent correlation between the presence of antibody and protective immunity and there is long duration of immunity for these core vaccines. The correlation in noncore vaccines has not yet been proven to the satisfaction of the major veterinary associations. If you prefer the ‘do it yourself’ approach, you can ask your vet or other appropriate health care provider to draw a blood sample which you can then send to Dr. Jean Dodds’ “Hemolife” service. For more information go to http://www.hemopet.org/services.html. Measuring titers is more expensive than revaccination, but may be a safer approach for geriatric or chronically ill dogs, and is the very best way to determine if vaccination of puppies has been effective.

Although the revised AAHA guidelines have been accepted by the major North American and International veterinary associations, many individual vets remain resistant to adopting them when developing their own vaccination protocols. That’s not too surprising when we consider that developing a custom vaccination protocol for each individual dog is more complicated than the old “hit ‘em with everything once each year” tactic that was the most common regimen for the past 50 years. Vaccinations, along with spay/neuter operations, are the bread and butter of many small animal veterinary practices so there is a financial incentive to stick with the old ways. Some vets believe that if they do not require annual vaccinations their clients will not bring their animals in for annual examinations. In all truth, even though professional animal care is referred to as veterinary “science”, I believe that some vets just don’t understand or believe the information that hard science has provided.

I’m not willing to say that one approach is better than another for all dogs or all teams. Every dog, every team, and every kennel is unique. I would however recommend that mushers download a copy of the current standard from the AAHA website (www.aahanet.org/PublicDocuments/VaccineGuidelines06Revised.pdf) and discuss the issue with his or her own vet. If the vet is recommending something that varies from the guidelines, ask the vet to provide his or her rationale for the difference. The published rules of both the Yukon Quest and Iditarod sled dog races require recent vaccination against parvovirus and canine distemper, along with a current rabies vaccination certificate. Your vet may be trying to help you comply with the rules of sled dog races in which you may wish to compete. The vet may also be aware of local conditions that make annual vaccination desirable or necessary. Any health care provider, either animal or human, should be willing and able to provide the logical and/or scientific rationale on which she or he bases any medical advice. If your vet isn’t willing or able to give you a science-based reason for an approach that differs from the guidelines you need to question why and if you are not completely satisfied with the answer you just might want to find a more currently educated or more cooperative veterinarian.

Going back to the saying that “every musher must drive his own team.”, here is the approach my veterinarian and I have decided to take for my Stardancer Historical Freight Dogs. Because all of my dogs are in frequent contact with dogs from other kennels and teams we will vaccinate all of them against bordetella (kennel cough). I have three geriatric dogs on my team who have been vaccinated throughout their lives, so I will pay the additional fee to measure titers for the core vaccines. If they are already immune there is no reason to accept the risks of revaccination.

Two of my dogs have been with me since puppyhood and vaccinated annually, and I know that my two Hedlund husky yearlings received their ‘puppy shots’ in accordance with the guidelines, so they are all good for two more years. Because I’m less certain of yearling Kia’s veterinary history she will be receive the core vaccines and then go into the recommended three year schedule.

By following the evidence-based approach to vaccination developed by the AAHA and accepted by the major national and international veterinary medicine associations I am confident that I can protect my dogs from dangerous infectious diseases while minimizing the risks of diseases associated with vaccines. It’s not the only approach, but it is the best approach for the Stardancer Historical Freight Dogs.

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