Special Report (June 16, 2006)

Opinion

Are our pets being over-vaccinated?
By Melissa Burden
Special to the Press

When you get a new puppy or kitten, veterinarians give them standard vaccinations to guard against infectious diseases. But scientists for years have been questioning the need for annual “boosters” for adult dogs and cats. Some studies have shown routine vaccinations can even cause cancer and other serious diseases in pets.

Though many veterinary colleges support newer vaccination guidelines, which reduce the need for some shots, the debate over whether we may be over-vaccinating our pets continues.

Jean Dodds, DVM, a world renowned vaccine research scientist, in Santa Monica, CA, told The Press many boosters are unnecessary.

“Why should we be giving pets foreign substances when they do not need them,” said Dodds, who has researched the vaccination guidelines for over 30 years. Veterinarians, she said, have been giving annual vaccinations simply because it’s assumed they are needed and were recommended by the United States Department of Agriculture.

“There never was any data that suggested vaccines must be given yearly,” Dodds said. “Veterinarians assumed there was data but there wasn’t.”

Vaccines like parvovirus and canine distemper are responsible for many diseases of the immune system in dogs, she contends. Anemia, arthritis, epilepsy, thyroid disease, liver failure, diabetes, allergies and other conditions, she believes, are linked to vaccines.

“Approximately five to 10 percent will develop problems,” Dodds said. “That increases to 20 percent in pure breeds.”

Irish Setters, Great Danes, German Shepherds, weimaraners and akitas are at higher risk of developing Hypertrophic Osteodystrophy, a bone disease that causes a 107 degree fever, pain, and the inability to walk as a result of vaccinations, she said.

“But there is really no breed that is not at risk,” she said.

The only vaccination needed, she asserts, is the rabies vaccine because it is legally required.

Dogs’ and cats’ immune systems mature fully at 6 months old, she explained. If canine distemper, feline distemper and parvovirus vaccines are given after 6 months, a pet has immunity for the rest of its life.

No effect

However, if another vaccine is given a year later, antibodies from the first vaccine neutralize the second vaccine, producing little or no effect.

Not only are annual boosters for parvovirus and distemper unnecessary, they subject a pet to potential risks of allergic reactions and immune-mediated hemolytic anemia, a life threatening disease that generally has unknown causes, said Dodds.

There is no scientific documentation to back up label claims for annual administration of these vaccines, she said.

A widespread belief that vets are over-vaccinating animals because annual shots account for a sizeable portion of their income “is just not the case,” said Dodds.

“Vaccinations only make up about 14 percent of a clinic’s income. The bigger problem is vets believe pet owners would not bring in their pets yearly if it were not for vaccines. Yearly exams for pets are crucial and may help a vet to diagnose early kidney and heart diseases. Vets believe that pet owners will be complacent and not bring them in which is why some stick to giving yearly vaccines,” she said.

Cancer

Tumors have been found at the site of vaccine injections in cats, though not dogs, according to an article published in the March/April issue of The Journal of the American Animal Hospital Association.

“Evidence suggests that like humans, dogs could be vaccinated with certain vaccines early in life and be protected for a lifetime, rather than receiving yearly doses,” says the article. “Reportedly, with the exception of rabies, the core vaccines, which protect against life-threatening disease, could last for seven years and should not be given more frequently than every three years. Rabies shots have a three-year duration, according to research, and should be given every three years.”

Dr. Bob Rogers, DVM, Critter Fixer Pet Hospital, in Texas, agrees.

“Dogs and cats no longer need to be vaccinated against distemper, parvo, and feline leukemia every year,” Rogers said. “Once the initial series of puppy or kitten vaccinations and first annual vaccinations are completed, immunity…persists for life. Not only are annual boosters for parvo and distemper unnecessary, they subject the pet to the potential risk of adverse reactions, he added.

Vaccines against Corona virus, Leptospirosis, and Lyme disease for dogs should be avoided, he said.

“The duration of immunity for vaccines for diseases like rabies, distemper, and parvovirus have been shown to be 7 years,” Rogers said. “More importantly it has been scientifically proven that, after the initial series, when vaccines are re-administered, the immune status of the patient is not enhanced. Antibodies from the initial vaccine block the subsequent vaccines from having any effect. In cats, the risk of Vaccine Associated Fibrosarcomas can be reduced by avoiding adjuvanted vaccines and unnecessary vaccines like chlamydia for cats.”

Dodds and Rogers suggest pet owners ask their veterinarians to perform vaccine antibody titer tests, which test antibodies for distemper and parvovirus annually after the initial series of vaccines.

Tests costly

“Titer tests are a tough issue,” Dr. David Boudouris, of Country Squire Animal Hospital, in Oregon said. “The tests are relatively expensive and there are many issues surrounding the results. We hope that if the titer is high that it means the animal is protected but there are questions surrounding the tests. They are expensive also. The test for rabies alone can cost $80 to $90.”

Pet owners should ask their vets about the duration and effectiveness of certain vaccinations, said Boudouris.

“The trend in veterinary medicine is to make sure we are not doing harm, that we are doing the best we can for our pets,” he said. “We do have options out there and we can assess what the animal’s needs are and go from there.”

Boudouris and his staff have embraced the concept of core vaccinations, such as rabies, parvovirus, distemper, and hepatitis (adenovirus) in dogs and feline distemper, feline leukemia, and rabies in cats.

“Clearly, certain animals may not need certain vaccines,” Boudouris said. “Not every dog needs giardia or lyme disease vaccinations. We have to assess the animal, know its lifestyle, and go on from there. New vaccine technologies have improved safety and efficacy. Diseases are never the same and new diseases emerge all of the time. We have modified our protocols in the past and will continue to constantly examine our program.”

In fact, Boudouris believes pets going without vaccinations may be more of a major clinical problem.

“We have an epidemic of parvovirus infection every year and see many cats with leukemia and respiratory diseases,” he said. “I probably see 60 dogs each year with parvovirus, a disease that is life threatening. Vaccines are important to an animal’s health.”

To report a suspected adverse reaction in your pet from vaccinations, call the Center for Veterinary Biologics - USDA Biologics Hotline at .

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