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Looking for the Best Defense

Denise Flaim | Animal House

February 27, 2001

YOU PROBABLY TAKE a shower every day, whether you need it or not, and change the oil on your car every 3,000 miles, just as the owner's manual recommends. And in all likelihood you vaccinate your dog and cat every year, as soon as that little postcard from the vet arrives in the mailbox.

But do you have to?

On those first two issues of hygiene and hydraulics, you're on your own. But when it comes to annual vaccines, some vets are re- examining the need to reflexively inoculate animals without determining if they actually need it.

"We veterinarians have been trained to follow annual vaccination protocols," says Allen M. Schoen, a holistic vet from Sherman, Conn., and author of "Kindred Spirits: How the Remarkable Bond Between Humans and Animals Can Change the Way We Live" (Broadway Books, $23.95). "But there is no scientific evidence for annual vaccinations. In fact, all the evidence is that vaccines last much longer than a year."

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So your pet might be overvaccinated-what's the big deal? In cats, there is a cancer issue: A small percentage of felines, about 1 in 10,000, develop sarcoma at the injection site. Some pets may have allergic reactions; more rarely, others have immunologic responses.

"If something doesn't need to be done, when you don't have to stick a foreign protein into the body, then the body may be better off without it," says Marc Franz of the Woodbury Animal Hospital. The tool that vets like Franz use to gauge whether or not a dog or cat has an adequate level of immunity is a blood test called a titer.

"When we look at immunologic response to a vaccine, there are two parts to that," Franz explains. "There's humoral immunity-that's what you think of as antibodies. And there's cell-mediated immunity, which is how cells react to things. The body needs both to fight a disease."

Titers measure only humoral immunity. "There is a leap of faith that's definitely grounded in science that assumes if you have good antibody levels you probably have good cell-mediated levels," Franz says. "The idea is if a dog has a protective titer, or a certain level of titer, then the dog probably doesn't need to be vaccinated."

In dogs, distemper and parvo are two diseases for which vets can routinely check the titer level, and "the feeling from Cornell [University College of Veterinary Medicine] is we can titer for Lyme disease, though the vaccine itself is still controversial," Franz says. Leptospirosis-a particular concern on Long Island, where outbreaks were noted last year-is a murkier proposition, with the most recent vaccine too new to determine what titer levels constitute protection: "At least historically," Franz says, "lepto titers did not stay high for a long period of time." And titering is not done for the Bordetella, or kennel cough, vaccine.

On the cat front, titering can be done for herpes, Calici virus and Panleukopenia virus, but not for the leukemia vaccine.

While it is possible to check titer levels for rabies in both cats and dogs, it is a moot point, Franz says, "since the health department does not accept rabies titers as evidence of protection- so as far as health code is concerned, you still need up-to-date rabies vaccines."

Titers are not "100 percent," Franz says, though he points out that vaccines aren't either. Done annually, however, titers provide a "comfortable understanding of protection."

Not all vets agree. "There hasn't been enough research to document what is the correct answer," says veterinarian Ned Horowitz of Massapequa Pet Vet, who prefers to err on the side of caution, citing the case of a client who did not titer but delayed reinoculating her Gordon setter for seven months, only to have it die of distemper. "I see one of those, that's enough for me."

Then again, Horowitz points out, there can be too much of a good thing. "Lyme, lepto, giardia-we talk the majority of our clients out of these vaccines," he says. "You talk to five vets, and you get eight different answers."

While organizations such as Therapy Dogs International accept titers in lieu of vaccinations for dogs that visit nursing home residents and hospitalized children, many boarding kennels and groomers do not. And it is more expensive to titer than vaccinate, because of lab costs. "And if your animal comes back showing a low antibody level, you would then have to vaccinate the animal anyway," Franz reminds.

Schoen advises owners to consider their pet's individual level of exposure before making decisions on vaccinations. "I tend to follow a middle path," he says. "If we overvaccinate animals, it predisposes them to immune-mediated diseases. But then again, if you bring your dog along with you to an animal shelter each week, it's really critical to have a defense."

Even though veterinary schools are re-evaluating vaccination protocols and titering is becoming more mainstream, Franz understands the concern among fellow vets. "For vets who remember seeing such tremendous losses during outbreaks of certain diseases-for myself, as an example, with feline leukemia-there's a definite and rational reluctance to back off vaccinating if we think it will lead to an increase of cases of infectious diseases.

"It's like a seesaw," he says. "You have to balance it."