Necessary or not?
Some veterinarians and pet owners are questioning vaccinations

By REBECCA T. DICKSON
Monitor staff
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June 12. 2005 8:00AM

A Labrador retriever in Maine developed a cancerous tumor. In South Carolina, a Basenji broke out in sores and nearly died. And a Los Angeles couple spent $6,000 on veterinary bills after their dog, Nikki, became violently ill.

A growing group of pet owners and veterinarians say illnesses like these seem to spring up after vaccinations meant to keep their pets healthy. While most animals don't suffer any ill effects from the preventive shots, and millions have been saved because of them, some people wonder whether the frequency of vaccinations is more a tradition than a necessity.

"It's important to realize that each dog and cat is unique," said Katherine Evans, a veterinarian at the Holistic Veterinary Center in Concord.

Puppies and kittens who receive timely vaccines will develop immunity later in life, she said. Before getting pets their annual booster vaccines, a blood test, or titer, can determine the level of immunity the dog or cat already has. And that will let a pet owner know if Fido and Fluffy are due for another round of shots, she said.

The only vaccine mandated by New Hampshire law is rabies, which must be administered every three years. As to the rest, some veterinarians and pet owners say less might be better.

Sandy Swain, a Labrador retriever breeder in Alton, said the last time one of her dogs received a vaccine other than rabies was about seven years ago. Swain said she keeps meticulous notes on her dogs' illnesses, among other things. When she reviewed them, she saw a pattern.
"Every spring, we'd go in and get the annual vaccinations, and then we'd spend the next four months back and forth to the vet with ear infections and skin infections," she said. "Then by the fall, that stuff would clear up, and we'd be okay. . . . I stopped vaccinating the older dogs, and I haven't had any problems. Ruby is 13. The last time she had (a vaccine), she was 6 years old."

Rick Palmquist, a Los Angeles veterinarian, surveyed animal clinics across the country that had vaccinated 100,000 dogs for distemper and parvovirus. He found that based on the initial shot alone, the animals were immune to the diseases anywhere from two years to more than 10.

Ronald Schultz, chairman of pathobiological sciences at the University of Wisconsin School of Veterinary Medicine at Madison, has been studying the efficacy of canine vaccines since the 1970s. "If a dog was effectively vaccinated as a puppy, and very certainly if it was ever vaccinated at a year old, it is immune for life," he told Newsday last month.

But not everyone is convinced over-vaccination is an issue. New Hampshire's state veterinarian, Clifford McGinnis, said he's not sure if the studies advocating less vaccination have been intensive enough to support the conclusion.

"If they can prove that parvo(virus) maintains an immune level for three years, fine. The manufacturer can write that on the product," he said. "I know there's a big push nowadays, where people feel they're over-immunizing animals. I don't know if they are or they aren't. I'd rather see some good scientific evidence.

"People get a tetanus shot now every 10 years. It used to be a lot less than that," he said. "But if I stepped on a rusty nail covered in horse manure, I'd go get another one."

Swain's 5-year-old yellow lab, Stella, has never had a vaccine other than rabies.

For distemper and parvovirus, Swain has blood tests done to determine her dogs' immunity levels. Sometimes they are protected, and sometimes they aren't. But even that doesn't dictate whether or when Swain will get them another shot.

For the remaining recommended vaccines, including distemper and parvovirus, Swain has blood tests done to determine her dogs' immunity levels. Sometimes they are protected, and sometimes they aren't. But even that doesn't dictate whether or when Swain will get them another shot.

Stella does not have antibodies for distemper, a contagious and often fatal viral disease that affects the respiratory, gastrointestinal and central nervous systems. Distemper was rampant in the 1950s but practically disappeared after the vaccine was created, although it's still present in wild animals, such as raccoons, skunks and foxes.

"But where would she pick it up?" Swain said. "I take her into the woods enough. But I feel like, what's the sense of giving her that shot? Distemper's not out there, so she's not going to catch it."

On the other hand, Swain said, her dog Shelby received the required rabies shot at 6 months, but a year later, she did not have an immunity level.

"That's funny to me. I had proof of her rabies vaccine. She would have been accepted anywhere she went, but she wasn't protected,"Swain said. "To me, I think it's more important to show that she has a titer than a rabies certificate. It can mean nothing."

The American Animal Hospital Association recommends administering vaccines every three years at most, rather than annually. Several canine vaccines such as distemper, rabies and parvovirus last between 7 years and 15 years, according to a recent study by the association.

A similar report, issued by the American Association of Feline Practitioners and the Academy of Feline Medicine and endorsed by AAHA, offers analogous vaccination guidelines for cats.

In 1991, three years after Pennsylvania issued a mandatory rabies vaccination requirement for cats, a lab at the University of Pennsylvania reported a connection between an increase in the number of sarcomas, or cancerous tumors, and vaccination in cats. It claimed that in some cats, rabies vaccinations were leading to an inflammatory reaction under the skin.

Soon after, the University of California at Davis reported that feline leukemia vaccines were also likely to cause sarcomas - even more so than rabies vaccines. Researchers now estimate the prevalence of vaccine-induced sarcomas to be as much as one cat in 1,000, or up to 22,000 new cases a year.

Pfizer Animal Health, a vaccine manufacturer, says the decision of how often and which vaccines to use should be left up to the veterinarians.

Vaccination schedules should be assessed each year, based on a pet's age, breed, health, environment and lifestyle (exposure to disease and other animals), the company said.

Swain said she didn't decide to stop vaccinating overnight: Even when the older dogs stopped getting annual boosters, she worried about doing the same with her puppies, which are supposed to receive immunity to many diseases from their mothers, she said.

"It takes courage," Swain said. "They put so much fear into you. They scare you to death that your dog or child is going to die if you don't do this.

"That's mainly because people don't have the facts about vaccinations and what's in them. I just feel confident enough in their health and nutrition. If they get anything, they'll be able to fight it on their own," she said.

"But the important thing here is if your puppy or dog (or cat) should contract these diseases, are you prepared to take care of healing them? I have a very good vet and a plan."

(Rebecca Tsaros Dickson can be reached at 224-5301, ext. 312, or by e-mail at rtsaros@cmonitor.com.)