Vaccine debate leaves profession in dilemma AVMA, AAHA positions attempt to ease contention

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Oct 01, 2002

Upper Montclair, N.J.- Dr. George Cameron knows canine distemper. He's witnessed rabies and parvovirus.

So when this second-generation practitioner hears warnings of vaccine overload, he scoffs: "I come from an era of having seen so much distemper and parvo, until I see otherwise that groups of animals shouldn't be vaccinated annually, I'll continue doing what I'm doing. I don't see harm coming to dogs from vaccinations, I see harm coming to dogs from not getting vaccinations."

Protocols like Cameron's are coming under attack as critics question the need for recurrent vaccines, associating annual inoculations with cancer or autoimmune disease. To allay dissension, the American Veterinary Medical Association (AVMA) promises to soon release a vaccine position statement and the American Animal Hospital Association (AAHA) anticipates canine vaccine guidelines. (See cover story.) But their direction doesn't offer clear-cut answers as federal regulators license vaccines based on up to a year of manufacturer efficacy tests, leaving a product's long-term side effects and duration of immunity largely unclear.

So in the manufacturer's absence, academics have stepped in, studying everything from immunization longevity to vaccine-associated sarcoma. Researchers claim the profession vaccinates too often using too many biologics, while vaccine supporters poke holes in their work. Their data, or lack of it, leaves veterinarians facing an ethical dilemma: practice outside the manufacturer's label, using personal judgment and limited research to determine risk, or booster annually, exposing patients to alleged harmful side effects.

No one protocol

Suspicious of anti-vaccine "propaganda," Dr. Gary Norsworthy, a feline practitioner in San Antonio, Texas, says he'll booster annually until he sees "hard evidence" not to.

"I want to see more substantiation for these researchers' claims," he says. "I agree with AVMA that there isn't enough data to know what the true duration of immunity is for the vaccines we use in dogs and cats, so I'm looking at my patients individually, doing risk assessments. I vaccinate with what I feel is appropriate.

"I can do it the way I think it's right and my neighbor can do it the way he thinks is right, and we may not agree."

Not quite a neighbor, New Yorker Dr. Mark Siebert considers yearly vaccinations unethical. A practitioner for 10 years, it wasn't until Siebert opened his own Manhattan clinic that he felt free to buck the norm. Now, in most cases, he vaccinates, boosters once and beyond that, relies on antibody titers to determine patient immunity levels. His clients, he says, are pleased.

"I don't know veterinarians around here who titer like this," he says. "But when I explain to clients why I don't see the need to vaccinate yearly, they understand. Ninety percent of my clients accept immunity levels as proof of protection."

Sarcoma spurs studies

Veterinarians like Siebert have questioned the overuse of vaccines and their side effects since their 1960s introduction to the profession. But it wasn't until 1991, when DVMs began noticing a high rate of soft tissue feline sarcoma developing at popular vaccination sites that the issue sparked debate. Cancer reports spurred studies and in 1996, veterinarians formed the Vaccine-Associated Feline Sarcoma Task Force (VAFSTF), which has pumped money into proving vaccine-malignancy correlations ever since. The research remains under way.

"Unless you're living in a cave, there's no veterinarian who's not going to be concerned with at least the information on the feline sarcoma issues," says Dr. Benjamin Cassutto, a practitioner in Delaware. "Even though I would profit more, I do not recommend certain vaccines because I'm worried about overstressing the immune system. This means you have to market better so you don't lose clients or income."

Greedy motives?

And profits are what vaccine critics believe is at the root of the profession's resistance to update its protocols. Without the lure of vaccines, clients might be less inclined to make yearly veterinary visits. Vaccines add up to 14 percent of the average practice's income, AAHA reports, and veterinarians stand to lose big, says Dr. Ron Schultz, a veterinary immunologist at the forefront of vaccine research and chair of the University of Wisconsin's Department of Pathobiological Sciences.

"I suspect some are ignoring my work," says Schultz, who claims some distemper vaccines last as long as 15 years. "Tying vaccinations into the annual visit became prominent in the 1980s and a way of practicing in the 1990s. Now veterinarians don't want to give it up."

Still, Cameron, who continues to vaccinate regularly, downplays talk of greed.

"But veterinarians are people who, after eight years in a university, come out with the lowest professional incomes," he says. "If it were just money, we wouldn't be in this business."

Associations take position

To help DVMs make sense of the controversy, the American Association of Feline Practitioners (AAFP) developed feline vaccine protocols based on VAFSTF research.

Canine-specific protocols also are on the way, AAHA promises, estimating their report's release by next spring. An AVMA position statement is scheduled for publication in coming months.

For North Carolina State University Professor Dr. Richard Ford, who worked on both the AAHA and AVMA documents, industry guidance couldn't come soon enough. "What concerns me is the large number of vaccines coming into the market, and the fact that there are veterinarians who insist on vaccinating every dog and every cat with every vaccine every year," Ford says. "We cannot do this; it's too much.

"Are we vaccinating too often with too many vaccines? I'm afraid the answer is yes."

Fact box

Income vaccinations represent in the practice

Practice Average

< $500,000 15.9%

> $1 million 2.3%

Total: 14.1%

Source: AAHA Financial & Productivity Pulsepoints, Second Edition