PETS DON'T NEED SHOTS EVERY YEAR
Experts say annual vaccines waste money, can be risky
Houston Chronicle Medical Writer
Debra Grierson leaves the veterinarian's office clutching Maddie and Beignet,
her Yorkshire terriers, and a credit card receipt for nearly $400.
That's the cost for the tiny dogs' annual exams, including heartworm checks,
dental checks and a barrage of shots.
"They're just like our children," said the Houston homemaker. "We would do
anything, whatever they needed."
What many pet owners don't know, researchers say, is that most yearly vaccines
for dogs and cats are a waste of money -- and potentially deadly. Shots for the
most important pet diseases last three to seven years, or
longer, and annual shots put pets at greater risk of vaccine-related problems.
The Texas Department of Health is holding public hearings to consider changing
the yearly rabies shot requirement to once every three years. Thirty-three other
states already have adopted a triennial rabies schedule. Texas A&M University's
and most other veterinary schools now teach that most shots should be given
every three years.
"Veterinarians are charging customers $36 million a year for vaccinations that
are not necessary," said Bob Rogers, a vet in Spring who adopted a reduced
vaccine schedule. "Not only are these vaccines unnecessary, they're causing harm
Just as humans don't need a measles shot every year, neither do dogs or cats
need annual injections for illnesses such as parvo, distemper or kennel cough.
Even rabies shots are effective for at least three years.
The news has been slow to reach consumers, partly because few veterinarians
outside academic settings are embracing the concept. Vaccine makers haven't done
the studies needed to change vaccine labels. Vets, who charge $30 to $60 for
yearly shots, are loath to defy vaccine label instructions and lose an important
source of revenue. In addition, they worry their patients won't fare as well
without yearly exams.
"I know some vets feel threatened because they think, `People won't come back to
my office if I don't have the vaccine as a carrot,' " said Alice Wolf, a
professor of small-animal medicine at Texas A&M and an advocate of
reduced vaccinations. "A yearly exam is very important."
The movement to extend vaccine intervals is gaining ground because of growing
evidence that vaccines themselves can trigger a fatal cancer in cats and a
deadly blood disorder in dogs.
Rogers conducts public seminars on the subject with evangelical zeal but thus
far has been unsuccessful in persuading the Texas Veterinary Medical Association
to adopt a formal policy.
"I'm asking the Texas attorney general's office if this is theft by deception,"
said Rogers, whose Critter Fixer practice won an ethics award from the Better
Business Bureau in 2000. "They just keep coming out with
more vaccines that are unnecessary and don't work. Professors give seminars, and
nobody comes and nobody changes."
When rabies shots became common for pets in the 1950s, no one questioned the
value of annual vaccination. Distemper, which kills 50 percent of victims, could
be warded off with a shot. Parvovirus, which kills swiftly and gruesomely by
causing a toxic proliferation of bacteria in the digestive system, was
vanquished with a vaccine. Over the years, more and more shots were added to the
schedule, preventing costly and potentially deadly disease in furry family
Then animal doctors began noticing something ominous: rare instances of cancer
in normal, healthy cats and an unusual immune reaction in dogs. The shots
apparently caused feline fibrosarcoma, a grotesque tumor at the site of the
shot, which is fatal if not discovered early and cut out completely. Dogs
developed a vaccine-related disease in which the dog's body rejects its own
"That really caused people to ask the question, `If we can cause that kind of
harm with a vaccine ... are we vaccinating too much?' " said Ronald Schultz, a
veterinary immunologist at the University of Wisconsin School of Veterinary
Medicine. "As you get more and more (vaccines), the possibility that a vaccine
is going to cause an adverse event increases quite a bit."
Less frequent vaccines could reduce that risk, Schultz reasoned. Having observed
that humans got lifetime immunity from most of their childhood vaccines, Schultz
applied the same logic to dogs. He vaccinated them for rabies, parvo, kennel
cough and distemper and then exposed them to the disease-causing organisms after
three, five and seven years. The animals remained healthy, validating his hunch.
He continued his experiment by measuring antibody levels in the dogs' blood nine
and 15 years after vaccination. He found the levels sufficient to prevent
Fredric Scott, professor emeritus at Cornell University College of Veterinary
Medicine, obtained similar results comparing 15 vaccinated cats with 17
nonvaccinated cats. He found the cats' immunity lasted 7.5 years
after vaccination. In 1998, the American Association of Feline Practitioners
published guidelines based on Scott's work, recommending vaccines every three
"The feeling of the AAFP is, cats that receive the vaccines every three years
are as protected from those infections as they would be if they were vaccinated
every year," said James Richards, director of the Feline Health Center at
Cornell. "I'm one of many people who believe the evidence is really compelling."
Texas A&M's Wolf said the three-year recommendation "is probably just as
arbitrary as anything else," and nothing more than a "happy medium" between
vaccine makers' recommendations and the findings by Schultz and Scott aimed at
reducing vaccine-related problems.
But many vets are uncomfortable making a drastic change in practice without data
from large-scale studies to back them up. There is no animal equivalent of the
U.S. Centers for Disease Control and Prevention, which monitors outbreaks of
vaccine-preventable disease in people, thus keeping tabs on a vaccine's
Federal authorities require vaccine makers to show only that a vaccine is
effective for a reasonable amount of time, usually one year. Richards notes that
studies to get a feline vaccine licensed in the first place are
typically quite small, involving 25 to 30 cats at most.
There is no federal requirement to show a vaccine's maximum duration of
effectiveness. Arne Zislin, a veterinarian with Fort Dodge Animal Health, the
largest animal vaccine maker in the world, said such studies would be expensive
and possibly inhumane, requiring hundreds of animals, some of them kept in
isolation for up to five years.
"I don't think anyone with consideration for animals would really want to go
through that process," said Zislin, another vet who believes current data are
insufficient to support an extended schedule.
Diane Wilkie, veterinarian at Rice Village Animal Hospital, said she tells pet
owners that vaccines appear to last longer than a year, but her office hasn't
officially changed its protocol yet. She said 20 percent to 30
percent of her cat patients are on the extended schedule.
"It's kind of a hard situation. The manufacturers still recommend a year, but
they're the manufacturers," Wilkie said. "It's hard to change a whole
professional mentality -- although I do think it will change."
In Houston, yearly pet examinations typically cost $50 to $135, with shots
making up one-third to half of the expense. A dental check, heartworm test,
fecal check and overall physical are usually included in the price. Without the
shots, vets could expect to lose a chunk of that fee.
But an increasing number of vets are emphasizing other services, such as
surgery. Wolf said savings on vaccines might prompt pet owners to get their
pets' teeth cleaned instead. An in-house test to check antibody levels is in
"I definitely think there's a profit issue in there; don't get me wrong," Wilkie
said. "(But) people are willing to spend money on their pets for diseases.
Although vaccines are part of the profit, they aren't that big a
part. We just did a $700 knee surgery."
Vaccination findings - Veterinary research challenges the notion that
pets need to be vaccinated every 12 months. Some of the findings:
Dog vaccines/Minimum duration of immunity
· Canine rabies - 3 years
· Canine parainfluenza - 3 years
· Canine distemper (Onderstepoort strain) - 5 years
· Canine distemper (Rockborn strain) - 7 years
· Canine adenovirus (kennel cough) - 7 years
· Canine parvovirus - 7 years
Cat vaccines/Minimum duration of immunity
· Cat rabies - 3 years
· Feline panleukopenia virus - 6 years
· Feline herpesvirus - 5 or 6 years
· Feline calicivirus - 3 years
Recommendations for dogs
· Parvovirus, adenovirus, parainfluenza, distemper: Following initial puppy
shots, provide booster one year later, and every three years thereafter.
· Rabies: At 16 weeks of age, thereafter as required by law.
· Bordatella: Use prior to boarding; may be repeated up to six times a year.
· Coronavirus: Not recommended in private homes. Prior to boarding, may be given
to dogs 8 weeks or older, and repeated every six months.
· Lyme: Not recommended.
· Giardia: Not recommended.
Recommendations for cats
· Panleukopenia, herpesvirus (rhinotracheitis), calicivirus: Following
initial kitten shots, provide booster one year later and every three years
· Rabies: At 8 weeks of age, thereafter as required by law.
· Feline leukemia: Use only in high-risk cats. Best protection is two
vaccines prior to 12 weeks of age, with boosters repeated annually.
· Bordatella: Use prior to boarding.
· Feline infectious peritonitis: Not recommended.
· Chlamydia: Not recommended.
· Ringworm: May be used during an outbreak in a home.
Sources: Ronald Schultz, University of Wisconsin School of Veterinary
Medicine; Fredric Scott, Cornell University College of Veterinary Medicine;
Colorado State University; University of California-Davis Center for
Companion Animal Health.