THERE’S NO PROOF that the
rabies shot killed Moolah and Mr. Schwartz didn’t immediately suspect any link. But
when the retired financial planner learned that some veterinarians are vaccinating pets
less frequently because of possible fatal side effects, he was furious. “No dog
should have to go through what Moolah did,” he says.
Evidence is building that annual vaccination of dogs and cats — performed for
diseases such as rabies, distemper and parvovirus — may not be necessary and could
even be harmful. Vaccines licensed by the U.S. Department of Agriculture are tested to
ensure they protect pets against disease, usually for one year. But the tests don’t
detect long-term side effects, or measure the duration of a vaccine’s effectiveness.
Recent and continuing studies at several universities suggest that protection from
vaccines may last for years, which would make annual shots for some diseases a waste of
money — at the very least.
Fears of vaccine-induced diseases date back more than 40 years. But a sharp increase
during the past decade in cancerous tumors among cats, between the shoulder blades where
vaccines typically are injected, has spurred studies. Some have found a
higher-than-expected incidence of side effects. “We see health problems in dogs for
which we have no explanation. The classic one is autoimmune disease,” says Larry
Glickman, professor of epidemiology at Purdue University’s School of Veterinary
Medicine in West Lafayette, Ind., who is studying possible links with vaccinations.
“We see an epidemic of hyperthyroidism in cats today, and we suspect that these are
happening because we’re over-vaccinating our pets.”
ACCUMULATIONS ARE THE DANGER
Dr. Glickman and his colleagues theorize that
repeated vaccination causes dogs to produce antibodies against their own tissue. The
antibodies are caused by contaminants in the vaccine introduced in the manufacturing
process. While the amounts are minuscule, they gradually accumulate with repeated
vaccinations over the years. But Dr. Glickman cautions that more research is needed before
a clear link can be established between antibody levels and autoimmune disease.
Vaccination recommendations for
cats and dogs vary around the country. Most states require rabies vaccinations every three
years, while a handful of states — as well as some individual cities and counties
— have mandated annual shots due to local problems with rabies in wild animals. Some
other vaccinations are given only when a pet’s lifestyle or environment exposes it to
a particular risk, such as Lyme disease.
Pet diseases other than rabies aren’t a threat to people, thus vaccinations
aren’t required by law. But veterinarians and vaccine makers have traditionally
recommended annual booster shots against potentially fatal diseases such as distemper and
parvovirus in dogs and herpesvirus in cats. In a policy statement last year, the American
Veterinary Medical Association acknowledged that the practice of annual vaccinations is
based on “historical precedent” and “not on scientific data.”
The emerging evidence of health risks is prompting
some vets to change their practices. “We’re now doing 40% less vaccinations than
five years ago,” says Kathleen Neuhoff, a veterinarian in Mishawaka, Ind., and
president of the American Animal Hospital Association, Lakewood, Colo.
FINANCIAL REASONS?
“My own pets are vaccinated once or twice as
pups and kittens, then never again except for rabies,” Ronald D. Schultz, chairman of
the University of Wisconsin’s Department of Pathobiological Sciences, wrote in the
March 1998 issue of Veterinary Medicine.
Some critics of annual shots accuse some vets of ignoring research about vaccine risks
for financial reasons. “Vets are afraid they will go broke” without regular
vaccines, which account for about 20% of their practice income, says Bob Rogers, a Spring,
Texas, veterinarian and outspoken critic of current practices.
Other vets deny that financial motives are involved.
(“No one who is motivated by money would ever become a veterinarian,” Dr.
Neuhoff says.) “The concern is that if we move too quickly to decrease vaccine
frequency across the board, we may be opening the door for some animals to become infected
when we could have prevented the problem,” says Todd R. Tams, chief medical officer
of VCA Antech Inc., in Los Angeles, the nation’s largest owner of veterinary
hospitals.
No one truly knows how long protection from vaccines
lasts. Vaccine makers say that proving their duration would be expensive and would require
large numbers of animals to be isolated for years.
One company, Pfizer Inc., decided to test its
one-year rabies vaccine on live animals and discovered it lasted for at least three years.
It sells the identical formula simply packaged under different labels — Defensor 1
and Defensor 3 — to satisfy different state vaccination requirements.
Copyright © 2002 Dow Jones & Company, Inc.
All Rights Reserved.
Reprinted with permission 8/01/02
