The need for annual vaccinations for cats and dogs is being questioned in veterinary
research circles, and some Inland Valley veterinarians have already changed procedures for
cats and may also do so for dogs.
Research showing that sarcomas, a type of cancer, were showing up at higher than expected rates on cats at points where injections were made prompted a research group called the Vaccine-Associated Feline Sarcoma Task Force to begin recommending less-frequent vaccinations for some cats.
"Instead of blanketing all cats with annual vaccinations, we're taking a look on an individual basis," said Dr. Mike Weigand, a veterinarian at Terra Vista Animal Hospital in Rancho Cucamonga.
The issue was highlighted nationally by a recent Wall Street Journal article that cited studies at several universities suggesting that "protection from vaccines may last for years, which would make annual shots for some diseases a waste of money -- at the very least."
"Evidence is building," the Journal article said, "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."
Cat vaccinations include shots for respiratory illnesses; feline panleukopenia, which destroys white blood cells; feline leukemia virus; and rabies, according to the American Veterinary Medical Assn.
Weigand said that for cats living indoors, he may recommend vaccinations at two-or three-year intervals rather than yearly. Indoor cats are at a much lower risk for an infectious disease than their counterparts roaming the neighborhood. Pet owners whose cats spend time outdoors should still get annual shots for the animals, Weigand said.
The veterinary community has been aware of the concerns about annual vaccinations for at least the last five years, Weigand said.
For dogs, there is speculation that the frequency of vaccinations and subsequent buildup of antibodies can trigger an autoimmune disease such as lupus, where a dog's own antibodies attack its cells instead of only the viral invaders.
"There's no real evidence to show the necessity of giving annual vaccinations -- it's more out of tradition," said Dr. Phillip Kass, a veterinarian and an associate professor at UC Davis who is researching vaccinations and their effects on dogs.
Kass said no connection to vaccinations and autoimmune diseases in dogs has been established, and a definitive answer on the topic would be several years away while a handful of research teams examine the issues. Another question is the duration of vaccines -- it's not known how long the shots are effective, he said.
The issue was cited in the Journal article, which noted that the American Veterinary Medical Assn., in a policy statement last year, acknowledged that the practice of annual vaccinations is based on "historical precedent" and "not on scientific data."
Dogs are vaccinated for distemper; parvovirus; leptospirosis, which attacks the kidneys; canine hepatitis; several respiratory diseases; and rabies, according to the AVMA.
Pet vaccinations will be one of the first subjects in preventive medicine classes when Western University of Health Sciences in Pomona enrolls its first class of veterinary students. Dr. Shirley Johnston, dean of the veterinary school, said students will have the benefit of current research findings on the subject.
While the frequency of vaccinations is an open question, pet owners concerned about the matter can have their veterinarians check their pet's immunity to certain diseases, the Journal article pointed out. A new 15-minute blood test, TiterChek, examines a dog's protection against two life-threatening diseases: canine parvovirus and distemper.
The test kit, approved by the U.S. Department of Agriculture, is made by a San Diego firm, Synbiotics Inc., which plans to market tests for cats.