Annual vaccinations may harm your pet
Inoculating your dog annually sometimes can do more harm than good. Experts say it's best to customize a program for your pet.
April 3, 2006
In her popular agility classes, Marcy Pratt of Lido Beach teaches dog owners to zoom their corgis through tunnels and sail their Australian shepherds over jumps.
But as she chatted with the handlers on the sidelines, she realized there was another area they needed help navigating.
"I found that most of them had their dogs vaccinated for everything, every year," Pratt says, even though the trend in veterinary medicine has been to tailor vaccine programs to a dog's lifestyle and risk. "And I had a couple of students whose dogs had had adverse reactions, including one that almost died."
The clarion call among veterinarians in recent years has been a movement away from reflexive annual "shots" and toward a more individualized approach: In its 2002 vaccine report for dogs and cats, the American Veterinary Medical Association rejected the idea of "one-size-fits-all" protocols, suggested that unnecessary overstimulation of the immune system might incur health risks, and divided vaccines into "core" and "non-core" categories.
A year later, the American Animal Hospital Association went a step further: In its landmark Canine Vaccination Guidelines, it added a third category - not recommended at all - and gave suggested intervals of vaccination for each vaccine. Earlier this year, the association published an update of the guidelines, adding some new information about specific vaccines and the vaccination needs of shelter dogs.
The original 2003 guidelines were "largely driven by the veterinary profession understanding that the way we have always done things may not be the way they will continue to be done," says veterinarian Michael P. Andrews of Riverside, Calif., the association's president. The fact that the 2003 protocols did not result in any obvious disease outbreaks reinforces the guidelines' message that "less is better," he says.
But as far as Pratt could tell from her students' stories, practice hasn't caught up with theory. So she organized a seminar by veterinary immunologist Ron Schultz of the University of Wisconsin School of Veterinary in Madison, arguably the expert's expert in the field of canine epidemiology. Since the 1970s, Schultz has conducted trials for manufacturers to determine duration of immunity, and he was on the task force that updated the association's guidelines. Seventy-five people attended the March 18 lecture in a church gym in Syosset; Pratt says a couple of local vets bought tickets, but she didn't see any in the audience.
Guidelines vs. habits
Schultz says that while some vets have kept up with changing times, old habits die hard. "We have a lot of work yet to change the attitudes of most vets in practice. We are trying to get them away from the annual thing and get them to understand that immunity doesn't stop on the precise day" that the vaccine expires.
The association's guidelines identify four vaccines as "core," or critical for every puppy to receive: distemper, parvovirus, adenovirus-2 and rabies. For the first three, the guidelines recommend a puppy series, a one-year booster and then revaccination no more frequently than every three years, if not less often. (There is no such flexibility with rabies, which, by New York State law, must be administered every three years.)
The remaining vaccines in the marketplace are either not recommended, or are considered "non-core," meaning that a dog's individual situation might require them. A pooch who lives in an area where leptospirosis is endemic - including parts of Long Island - might be a candidate for that short-lived vaccine; ditto for one owned by globe-hoppers who spends time at a boarding facility where bordetella (kennel cough) is a constant possibility.
Schultz says some vets resist this nuanced approach to vaccination because of habit and economics. Urging a client to come in for annual shots is more compelling than a postcard cheerily announcing that it's "wellness exam" time.
"There's no evidence that a one-year requirement improves compliance with vaccination," Schultz adds. "At one point, it was thought if we make people vaccinate every year, we're going to vaccinate more dogs. What it turned out to be was that we were having the same dogs revaccinated annually."
Labels aren't guidelines
Another problem is byzantine labeling and clever marketing on the part of vaccine manufacturers.
"The label means nothing," Schultz says simply, noting that vaccines licensed for one year and three years are often the same product. "The label has an arbitrary and capricious annual revaccination requirement, and it takes an act of Congress to take it off" - literally. Schultz says the Department of Agriculture has applied to remove the language, a legislative process that he estimates will take seven years.
While many veterinary colleges have moved toward vaccine protocols of every three years for core vaccines that are "modified live viruses," or MLV, such a parvo, distemper and adenovirus, others suggest that immunity lasts far longer - Schultz among them. "Duration of immunity is whatever is determined by the studies, and those studies show that duration of immunity is seven to nine years, which is a lifetime."
Too much, too soon
Veterinary immunologist Jean Dodds of Santa Monica, Calif., another popular lecturer on the vaccine topic, stresses that overvaccination can overwhelm the immune systems of dogs, in particular certain purebreds that are genetically predisposed to adverse reactions. (In a recent study by veterinarian George Moore of Purdue University in West Lafayette, Ind., dachshunds, pugs, Boston terriers, miniature pinschers and Chihuahuas showed the highest rate of adverse effects to vaccines.)
"The recently weaned young puppy or kitten entering a new environment is at greater risk here, as its relatively immature immune system can be temporarily or more permanently harmed," says Dodds. "Consequences in later life may be the increased susceptibility to chronic debilitating diseases."
Dodds adds that because vaccine labels themselves state that vaccines should only be given to healthy animals, owners should not vaccinate chronically ill animals, adding that they can even apply to their state for a waiver of the rabies vaccine requirement if their vet writes a letter documenting the animal's frail health.
For owners who worry about their dogs' immunity lapsing, Dodds recommends titers, or blood tests that can measure antibody levels.
But being progressive while the rest of the world inches to catch up can be frustrating. Karen Tragesser, 50, of Lynbrook, takes her 8-year-old golden retriever, Dillon, to Pratt's classes. She says her vet has "never been one to push vaccination," and Dillon gets a booster only every three years. With a new puppy on the horizon, and Dillon getting on in years, Tragesser is thinking of titering for "core" diseases such as distemper, parvo and adenovirus.
"If you want to do activities with your dog, you need proof of current vaccination," including the above trio, Tragesser says. The group that certifies Dillon as a therapy dog will not accept titers as proof that he is adequately protected, and so she will have to choose between doing what she feels is best for him health-wise - and letting him make visits to hospitals and nursing homes.
As for Pratt, she's left with the acronym that Schultz used to open his lecture. "He said every dog needs TLV - training, love and vaccination," she says.
The key is that only the middle one needs to be unlimited.
To read the American Animal Hospital Association's complete 2006 Canine Vaccination Guidelines, go to www.aah
LESS IS MORE FOR CATS, TOO
When it comes to progressive attitudes about vaccination, cats were way out ahead.
"We were the first out with vaccination guidelines in 1997-98," says veterinarian James Richards of the Cornell Feline Health Center in Ithaca, N.Y., and past president of the American Association of Feline Practitioners.
One of the motivators was the incidence of injection-site sarcomas in cats. "Even though it's a rare event" - Richards puts the "best estimate" at one to three out of every 10,000 vaccinated cats developing cancer at the vaccination site - "it's a very serious one. "
As with dogs, reflexively vaccinating felines was the order of the day until 15 or so years ago. "Back when I started as a vet, we had vaccines for three or four infectious cat diseases, and we didn't think a whole lot about how often they needed to be given," he says. "At this moment, we have vaccines for 10, in various combinations. "
Richards urges cat owners to think about vaccines as a double-edged sword: necessary medical procedures that also have their risks and downsides. "Vaccination is an elective medical procedure that's going to be individual for each critter instead of a knee-jerk sort of thing. Becoming informed yourself is very important. "
To that end, he encourages cat owners to discuss vaccination with their vet - and if their vet is unresponsive to their questions, to find someone who does respond. A good starting point for discussion is the current association guidelines, available at www.aafponline.org
- for now, at least. Richards is convening an international panel of feline specialists to revisit the guidelines, a process he hopes to complete by summer.
While he doesn't know precisely what the update will say, he can guess the tune: "The key is using the right vaccines absolutely only as often as we need," he concludes. "Most assuredly, less is more."
- Denise Flaim
Copyright 2006 Newsday Inc.