che ne pensate?
voi li vaccinate ogni anno?
intanto eccovi la mia signorina
Shots in the dark
Would you be surprised to discover your pet's veterinarian was recommending an unnecessary and potentially dangerous medical procedure -- every single year?
Unfortunately, recent research suggests that's exactly what's happening in far too many veterinary practices.
The procedure is the annual "booster shot" for dogs and cats, intended to prevent infectious diseases, many of them life-threatening, in our pets.
But just as we don't get our childhood immunizations "boosted" every year, it turns out our pets don't need that either -- at least for common viruses like canine parvovirus, canine distemper, feline panleukopenia and even rabies.
"A practice that was started many years ago and that lacks scientific validity or verification is annual revaccinations," wrote vaccine researcher Dr. Ronald Schultz in "Kirk's Current Veterinary Therapy." "Almost without exception there is no immunologic requirement for annual revaccination. Immunity to viruses persists for years or for the life of the animal."
Those words were not written by some renegade anti-vaccine conspiracy theorist; Schultz is chair of the department of pathobiology at the University of Wisconsin-Madison School of Veterinary Medicine and editor of the textbook "Veterinary Vaccines and Diagnostics." And they appeared in "Kirk's" -- the bible of veterinary practice -- in 1992.
To those pet owners who only recently became aware that annual "booster shots" don't reflect the best scientific thinking of today, that publication date probably comes as a surprise.
In 1992, the annual visit to the veterinarian for "booster shots" was the virtually unquestioned hallmark of the responsible pet owner, and an important part of how veterinary practices paid their bills. It's not hard to believe that almost no one took notice back then.
But the scientific case against annual vaccination continued to grow, and in 1998 Colorado State University School of Veterinary Medicine became the first veterinary college to issue a vaccination schedule that recommended against the practice, issuing a statement about its new guidelines that read:
"We are making this change after years of concern about the lack of scientific evidence to support the current practice of annual vaccination and the increasing documentation that over vaccinating has been associated with harmful side effects. Of particular note in this regard has been the association of autoimmune hemolytic anemia with vaccination in dogs and vaccine-associated sarcomas in cats ... both of which are often fatal."
Today, not one veterinary college in the United States recommends annual re-vaccination for all cats and dogs. Neither do the American Animal Hospital Association, the Vaccination Guidelines Group (VGG) of the World Small Animal Veterinary Association (WSAVA), the American Association of Feline Practitioners nor the Academy of Feline Medicine.
In fact, it's safe to say that the routine administration of yearly shots has pretty much gone the way of the eight-track tape, at least as far as the science goes.
Unfortunately, change has been slow inside the offices, clinics and hospitals where America's pet owners get health care for their dogs and cats.
In 2004, Kate O'Rourke
reported in JAVMA, "Many veterinarians have responded to the three-year guidelines with resistance."
At the time, O'Rourke quoted vaccine researcher Dr. Richard Ford as saying, "It was truly a bitter pill, and we did not take this well ... Despite growing acceptance of the guidelines, there is still considerable resistance."
Even as recently as last year, vaccination protocols hadn't changed all that much in many veterinarians' offices, according to a paper published in the "Journal of the American Veterinary Medical Association." Veterinarians, it seems, were still widely ignoring new vaccine protocols meant to protect cats from a dangerous type of tumor caused by vaccines.
"In 1991 veterinary medicine suffered a disturbing revelation," wrote Bay Area veterinarian and Dogster.com blogger Dr. Erich Barchas about the report. "Two commonly used feline vaccines were linked to the development of malignant tumors at the site of vaccination ... They occur in approximately one out of every 3000 - 10,000 cats who receives a rabies or leukemia vaccine." The tumors were dubbed "Vaccine Associated Sarcomas," or VAS.
That discovery prompted a major revision of feline vaccination protocols, including minimizing the number of times a cat receives an injection to lessen the risk. Veterinarians were also advised to administer vaccines in the legs instead of between the shoulder blades, to allow the leg to be amputated if a tumor developed.
While many veterinarians did change their practices, a troubling number of them did not. The incidence of tumors in the area between the shoulder blades dropped in the years following the new recommendations, but only from
53 to 40 percent of the tumors.
Worse, while some veterinarians were clearly vaccinating cats in the limbs, they were doing so too close to the main part of the body, where they're still difficult to treat. The incidence of such injection site sarcomas in cats' legs rose from only 1.1 percent to nearly 10 percent. Clearly, many veterinarians know enough to shift the vaccination site to the leg, but not enough to understand the injection needs to be given in the lower part of the leg, to allow for amputation if a tumor develops.
So, what's behind veteranarians' resistance to adopting new vaccine protocols? Why are so many of them ignoring, rejecting or simply unaware of the changed guidelines?
First, it's important to realize that many veterinarians have changed their approach to canine and feline vaccinations. But last year's JAVMA report suggests such changes are far from universal.
Those veterinarians who have made no changes, or minimal ones, in their approach to dog and cat vaccination typically fall into one of three camps:
The first group includes those who stubbornly insist, contrary to overwhelming scientific evidence, that reducing the frequency of re-vaccination may lead to the resurgence of now-rare diseases like canine distemper. As Schultz has pointed out, re-vaccinating already-immune dogs and cats does nothing to protect the unvaccinated pets who are actually at risk.
The second group consists of vets who simply don't know or don't care what the science says; they're just going to do what they've always done, and have no interest in changing. I know this because I've had the unfortunate, although thankfully rare experience of meeting veterinarians who had no idea there was an almost-20-year controversy over re-vaccination.
The third camp is comprised of veterinarians worried about the bottom line.
For years, pet owners were encouraged to bring their pets in for annual shots, in part as a means to schedule an annual health exam. The shots themselves didn't bring in much money, but the annual visit was an important source of base revenue for many practices.
Losing that annual exam income would devastate some practices -- or, as one vaccine manufacturer diplomatically
put it in a 2005 booklet meant to educate veterinarians about the new guidelines, "Some veterinarians have delayed incorporation of extended vaccination protocols based on economic concerns."
Schultz agrees that economics are a major factor in veterinarians' resistance to change. In a speech at the 2007 National Parent Club Canine Health Conference, he said many veterinarians have told him, "I believe the duration of immunity for some vaccines like distemper, parvovirus and hepatitis is many years, but until I find another way to get the client into my office on a regular basis I'm going to keep recommending vaccines annually."
All this leaves pet owners in an awkward position. Because the lack of compliance with new guidelines is so widespread, we're forced to essentially grill our pets' veterinarians for the basis of their vaccine protocols. This can create a real communication problem, because many veterinarians get annoyed at being second-guessed by laypeople who question even the most basic statements of medical fact because of something they read on the Internet or heard from a friend.
But if all these years later, and for whatever reason, some veterinarians are still ignoring the science that tells them routine annual vaccination is not necessary and can be harmful, and that special precautions need to be taken when vaccinating cats, what choice do pet owners have?
However hard it might be, we have to make sure our veterinarians are making their vaccine recommendations on the basis of science, not habit or revenue.
Before complacently accepting a vaccine protocol for your pet, make sure you've done your homework on the issue -- and that your pet's veterinarian has, too.
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