We Overvaccinating Our Pets?
Excerpt by Jenette Restivo, ABCNews.com
may get notices from the veterinarian every year or two suggesting
you revaccinate your pet for distemper, leukemia or other diseases.
But now some vets are wondering whether the repeated doses can
do more harm than good.
a pet owner, you've seen them in your mailbox - postcards from
the neighborhood veterinarian reminding you that it's time for
Fido's distemper vaccine or Fluffy's leukemia shots.
vaccines are a standard in health care. We vaccinate our children
against hepatitis, polio and influenza when they're infants and
toddlers, giving up to two boosters of some vaccines until puberty.
But then we stop.
Not with our
pets, though. In fact, we continue bolstering the immunity of
our pets until they are well into their senior years. That has
spawned a debate as fierce as any fighting pit bull: To vaccinate
or not to vaccinate.
believe the practice of annual vaccinations is an unnecessary
evil, responsible for such diseases as allergy, seizures, anemia,
even cancer. They say vaccinations make our animals vulnerable
to some of the top diseases plaguing our pets, and that rather
than building up immunity we are overwhelming their immune systems.
Others would rather stick to tradition and say that vaccinating
has warded off the most deadly animal diseases over the past 30
years, so why question it now.
Lack of Scientific Evidence
Dr. W. Jean
Dodds, president of the nonprofit animal version of the Red Cross
called Hemopet, was one of the pioneers of the vaccine debate,
an issue she says has been percolating for the past 10 years.
She says as the profession started looking into exactly how the
recommendations for annual vaccines arose, they started realizing
that they were just that recommendations. And in fact,
they were not based on scientific evidence.
that after 20 years of following the United States Department
of Agriculture and the drug manufacturer's recommendations to
make annual vaccines a standard in veterinary care, professionals
who first challenged the standard school of thought were considered
rebels. Her arguments were challenged by other veterinary professionals
whose belief in the duty to vaccinate was galvanized by episodes
such as the deadly parvo virus epidemic in the late 1970s that
killed thousands of dogs and was only halted by mass administration
of the parvo vaccine.
says an unfortunate observation led many vets to begin to reconsider
current vaccination protocol. In 1991, three years after Pennsylvania
issued a mandatory rabies vaccination requirement for cats, Dr.
Mattie Hendrick's lab at the University of Pennsylvania noted
a connection between the surprising increase in the number of
sarcomas, or cancerous tumors, and vaccination in cats. It seemed
that in some cats, rabies vaccinations were leading to an inflammatory
reaction under the skin.
researchers at the University of California at Davis showed that
feline leukemia vaccines were also likely to cause sarcomas, and
to an even greater degree than the rabies vaccine. Further investigating
led researchers to estimate the prevalence of vaccine-induced
sarcomas to be as much as one cat in 1,000, or up to 22,000 new
cases of sarcoma a year.
professionals began to suspect vaccination as a risk factor in
other serious auto-immune diseases. Researchers surmised that,
in some animals, vaccines were stimulating the animal's immune
system against his or her own tissues, leading to potentially
fatal diseases such as auto-immune hemolytic anemia (AIHA) in
dogs. Researchers began to suspect delayed vaccine reaction for
the cause of such chronic conditions as thyroid disease, allergy,
arthritis and seizures in cats and dogs.
led to a 1995 Journal of the American Veterinary Medical Association
article that concluded there is "little scientific documentation
that backs up label claims for annual administration of most vaccines,"
and that the only vaccine tested routinely for duration is the
rabies vaccine. In addition, the article suggested that though
some vaccines should be given annually, giving others only every
few years would be sufficient because of potential risks associated
Hesitation to Vaccinate
that in her own practice, she only vaccinates when necessary.
Rather than automatically giving boosters, Dodds gives annual
titers, or tests, to check the level of antibodies (disease fighting
cells) in the blood to determine if boostering is necessary. Though
she expects that immunity would be conferred for life, she says
that titers offer "an added measure of security."
vets have in fact begun to change their vaccination habits, many
continue to administer annual shots. Dodds believes that the resistance
is not so much a financial issue since vets should still asks
clients to come in for an annual check-up and titers. Rather,
it's more about changing attitudes.
we were told that this is what we had to do," Dodds says. "The
USDA put the recommendation on the label. Our confidence was totally
Non-Vaccination a Greater Danger?
vets believe it's too early to change procedure. The say that
until more is known about the immunity conferred by some vaccines,
it's best to take a conservative approach. They emphasize the
fact that annual vaccinations have been effective at decimating
the incidence of formerly common, potentially lethal viral diseases
such as feline panleukopenia, rhinotracheitis, feline leukemia,
canine distemper, hepatitis and canine parvo virus. And with the
incidence of the deadly feline leukemia virus so high, it is too
hard and too risky to determine which cats are at risk.
Klingborg, former Chairman of the Council of Biologic and Therapeutic
Agents of the American Veterinary Medical Association (AVMA) and
Assistant Professor at the University of California at Davis,
says that while the vaccination issue is a complicated one, nonvaccination
is a major error.
"In most cases,
the threat to the animals' health from nonvaccination is much
greater than vaccination," he says. "The diseases are real, severe
says the vaccination debate could be settled by more information
on the duration of immunity most vaccines impart.
Conclusive Answers Difficult
vaccine companies are under no legal obligation to demonstrate
duration of immunity, that question may remain unanswered for
Wynn, a Georgia-based veterinarian and former board member of
the American Holistic Veterinary Medical Association says that
the problem with obtaining immunity duration information is monetary
would have to be gained by challenge studies in which you give
viruses to animals inoculated over five to 10 years ago," she
says. "You would have to keep those animals in a controlled environment
for this time only drug companies have that kind of money."
that for the drug companies, the decision is based on priorities
it's either more products or immunity studies, not both.
Reference Source 104
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