By Kim Campbell Thornton
April 1, 2010
With his twinkly eyes and beautiful white beard, veterinary immunologist Ronald D. Schultz bears a passing resemblance to Santa Claus. He even appears to share Santa’s rock star status, always crowded ’round with people who want to ask him questions.
Dr. Schultz’s passion is canine and feline vaccination programs (well, his real passion is cattle, but that’s another story), and you can tell it when he speaks. I’ve heard him twice recently, first at the American Animal Hospital Association meeting in Long Beach (hi Jason!) and a week later at the Safer Pet Vaccination and Health Care seminar in Del Mar, where he and Jean Dodds were the featured speakers at a day-long event to raise money for the Rabies Challenge Fund Charitable Trust.
That’s a nonprofit with the dual goals of proving that the duration of immunity for the rabies vaccine is longer than three years and establishing a blood titer standard that would allow pet owners to avoid giving their animals unnecessary rabies booster vaccinations, which are linked to autoimmune disease, skin and digestive problems, injection site tumors and other adverse reactions. The event drew approximately 210 attendees and raised at least $30,000, with a possibility of more if further donations come in to take advantage of the remaining $6,500 in matching funds put up by two anonymous dogs.
At both AAHA and Safer Pet, I was looking forward to hearing about the progress being made in changing veterinary hearts and minds about the frequency of vaccinations–the need for decreasing them, that is. But it looks like a lot of education is still in order.
I’ve been attending sessions at vet conferences for a good 20 years now. I don’t know that I could stand up there and give a talk on vaccinations just off the top of my head, but I feel like I have a reasonably good grasp of the subject. So I was a little surprised at AAHA when I slipped into Dr. Schultz’s presentation and heard what seemed to be a pretty basic talk on vaccinations: the differences between modified live and killed vaccines, core and non-core vaccines and when each should be given, and how often vaccines should be boostered.
When I introduced myself to him in Del Mar, I asked about that. “Don’t they already know that stuff from vet school?”
Not necessarily, he told me. Not a huge amount is known about immunology, so it sometimes gets short shrift. Immunology is a very new science and so complex that immunologists know only a little part of it. As he told the AAHA group, vaccination is the easiest yet most complex medical procedure a veterinarian will ever perform. It’s also surrounded by misconceptions. Just a few that he’s heard from practitioners:
If the vaccine label recommends annual revaccination, that’s proof that immunity lasts for only one year. False
If the animal is not revaccinated at or before the age of 1 year, the whole vaccine program must begin again. False.
Even if annual boosters aren’t necessary, they won’t hurt. False.
What we do know:
Vaccinating too often confers no benefit.
The minimum duration of immunity for canine distemper, parvovirus and adenovirus-2 vaccines (the core vaccines, which are considered essential and should be given to every dog) is seven to nine years, and they are essentially 100 percent effective.
Running the risk of adverse reactions, no matter how low, is unacceptable medical practice.
At both events, Schultz emphasized that only 50 percent of all puppies in the U.S. get vaccinated and only 25 percent of all cats. To reduce the incidence of disease, it’s better to vaccinate more animals than to vaccinate the same ones year after year. Schultz would like to see 70 percent of puppies get vaccinated to provide better population, or herd, immunity, but only with core vaccines and only as often as needed. “We need to find a way to get more animals immunized at least once,” he says.
The current AAHA vaccination guidelines call for a puppy to receive a final dose of core vaccines at 14 to 16 weeks, followed by a booster at 1 year. After that, core vaccines should be given at a minimum interval of every three years or longer. The recommendations by the American Association of Feline Practitioners are here. Non-core vaccines–things like lepto or giardia–are advised only if the animal is at high risk of the disease.
The AAHA recommendations are a middle-of-the-road approach. A minimalist, like Schultz, would give rabies (the other core vaccine) every three years, as required by law, and would never give the core vaccines again.
How old should a puppy be when the first vaccine is given? Eight to 10 weeks is the earliest Schultz would start vaccinating. The exception, he says, is shelter animals, which can be started at 6 weeks. “I’m very liberal regarding vaccination of shelter animals and very conservative regarding vaccination of pets.”
Note to horse people: None of this applies to you. Horses don’t have a great immune system, equine vaccines are less effective than those for dogs and cats, and they often have a very short duration of immunity.
I don’t want to leave out Dr. Dodds, who is a rock star in her own right in the holistic veterinary community and an internationally recognized expert on immunology. Her talk focused on the benefits of vaccines, vaccine-associated risks, titer testing and current issues surrounding vaccination.
The takeaway–Dodds suggests these alternatives to current vaccination practices:
Measure titers, if for no other reason than peace of mind or proof of immunization to boarding kennels. “The presence of any measurable antibody shows protection,” she says.
Be cautious in vaccinating sick animals or animals with a fever. Vaccines are meant for use in healthy animals.
Avoid revaccinating animals with prior adverse reactions, and don’t use them for breeding.
Be aware of and tell clients about factors that increase the risk of vaccine reactions in dogs and cats: young adult age, small-breed size, neutering, and multiple vaccines given per visit.
Know which breeds and types of dogs are at risk of adverse reactions. They include Akitas, Weimaraners and small white-coated breeds.
Avoid unnecessary (non-core) vaccinations or too-frequent vaccinations.
She says veterinarians need to understand duration of immunity, accept the potential for adverse events (aka vaccine reactions), recognize adverse events rather than dismissing or denying them, inform clients of the issues surrounding vaccinations and of options such as titers or less frequent vaccination, and become educated about breed and other predispositions. When veterinarians don’t do those things, the public loses trust in them and the principle of “do no harm” is violated.
Does all of this mean that there are hard and fast rules about exactly when to vaccinate, which vaccines to use and how often? Nope. Schultz says pets need an individualized vaccine program based on their lifestyle, health, medical history, age, the prevalence of disease in the area and other factors.
If you’d like to purchase a video of Dr. Dodds’ presentation and the Q&A session with Dodds and Schultz or a copy of the program guide, which contained several articles by both, sign up here. You’ll be contacted when they’re available, and the proceeds benefit the Rabies Challenge Fund.
Your virus trivia for the day: human measles, canine distemper and rinderpest (cattle) viruses are all members of the same genus — Morbillivirus — and are virtually identical.