Still vaccinating your pet every year?
That may not be necessary and could even cause harm
By Kim Campbell Thornton
Special to MSNBC.com
Updated: 10:48 a.m. ET July 18, 2005
Vaccinations have saved many pets' lives over the years, but they
aren't without risk. Now, with new research showing that immunity may
last longer than once thought, veterinary experts say it's safer to
decrease the frequency of most shots that typically have been given
Side effects from vaccinations range from mild itching and swelling to
anaphylactic shock leading to death. Cats may develop vaccine
sarcomas, which are cancers that develop at the site of the injection.
And dogs may develop certain autoimmune diseases.
Veterinarians have suspected for years that annual vaccinations for
cats and dogs aren't necessary, but large, well-controlled studies
just didn't exist to prove it one way or the other. With the exception
of rabies vaccine, the U.S. Department of Agriculture doesn't require
data beyond one year for any vaccine.
With that being the case, vaccine manufacturers arbitrarily
recommended annual vaccinations, and most veterinarians, concerned
about liability issues, concurred.
Sometimes immunity lasts a lifetime
More recently, however, several published studies have shown that
immunity provided by some vaccines lasts for much longer than one year
and in some cases for a lifetime.
"We know that for [canine] distemper and parvo, for example, the
immunity lasts a minimum of five years, probably seven to nine years,
and for some individuals for a lifetime," says veterinarian Jean
Dodds, founder of Hemopet, the first nonprofit national blood bank
program for animals, located in Santa Monica, Calif.
"For cats, so far we have challenge data out nine years showing that
immunity is still protective," says Dodds. And with rabies vaccine,
new data indicate the immunity lasts for at least seven years, she says.
What does all this mean for your dog or cat? As with many other
aspects of veterinary medicine, vaccinations are becoming
individualized, but in most cases, fewer and less frequent
vaccinations are the way to go. Most animals need only what are known
as core vaccines: those that protect against the most common and most
serious diseases. In dogs, the core vaccines are distemper,
parvovirus, hepatitis and rabies. In cats, they are panleukopenia,
calicivirus, rhinotracheitis (herpesvirus), and rabies as required by law.
Three-year interval recommended
"Current vaccine protocol is to properly immunize puppies and kittens
with two or three doses, starting later than we used to, maybe at
eight weeks and not earlier than six weeks," Dodds says. "Then you can
give a booster at one year and either repeat it every three years,
stagger it by giving one vaccine per year instead of combination
vaccines, or do titers instead." Titers are tests that measure the
level of antibodies in the blood, which would indicate that immunity
That recommended three-year interval was a compromise decision.
"Annual boosters for the core vaccinations are excessive for most dogs
and cats," says veterinarian Link Welborn of North Bay Animal and Bird
Hospital in Tampa, Fla., and a member of the most recent panel of
veterinarians that revised vaccination guidelines for dogs and cats.
"Limited studies suggest that booster vaccinations for many of the
core vaccinations last for at least seven years. However, given the
limited number of animals involved in these studies, three years
seemed like a reasonable compromise."
There's also an advantage to giving single rather than combination
vaccines. "Giving more vaccinations increases the likelihood of side
effects," Welborn says. "Separating vaccinations allows the
veterinarian to determine which vaccine caused a side effect if one
If you're concerned that your dog or cat will develop a
vaccine-related health problem, but you want to make sure they're
protected against disease, annual titers are an economical alternative.
They're reliable and costs are comparable to those for vaccinations.
For instance, at Canyon Animal Hospital in Laguna Beach, Calif., the
rate for a combination distemper/parvo titer is $39. If the dog turns
out to need a vaccination, it's given at no additional charge. Titers
are also available for cats.
Consider changing veterinarians if yours claims that titers are too
expensive to perform, charges $50 or more for them or wants to
vaccinate because a titer level is "too low."
"Any measurable titer to a specific antigen means you've got immune
memory cells," Dodds says.
Skip the annual exam, too?
So do these new recommendations mean that your dog or cat no longer
needs an annual veterinary exam? Don't get your hopes up.
The physical exam your veterinarian performs is far more important
than vaccinations. In a recent study on longevity, 16 percent of dogs
and 20 percent of cats were found to have subclinical ? meaning signs
weren't yet obvious ? diseases that were diagnosed through an exam and
routine lab work.
"Many people, because the animal is living with them, don't notice
subtle changes in the behavior or the clinical state of the animal
that a veterinarian would notice," Dodds says.
Welborn likes to see veterinarians and pet owners working together to
perform an annual lifestyle risk assessment. That means looking at the
animal's environment and habits to decide whether it needs such
non-core vaccines as those for feline leukemia or Lyme disease or
canine cough (probably not, unless the exposure risk is high) and
whether it needs changes in diet or exercise levels to prevent obesity
and its attendant problems, which include arthritis and diabetes.
"Care should be individualized for each pet," Welborn says. "The days
of treating all dogs and cats the same are gone."
Kim Campbell Thornton is an award-winning author who has written many
articles and more than a dozen books about dogs and cats. She belongs
to the Dog Writers Association of America and is past president of the
Cat Writers Association. She shares her home in California with three
Cavalier King Charles Spaniels and one African ringneck parakeet.