Less Is More: A New Perspective on Annual Vaccinations
The Bark, Summer 2004
Darrlyn Alexander's brown Standard Poodle puppy, Mocha, was ill much of her first year of life. She suffered from eye infections, chronic ear infections, and daily bouts of diarrhea and vomiting. Medications prescribed by her veterinarian brought little relief. Alexander, of Totowa, New Jersey, was a responsible pet owner, and had been careful to vaccinate Mocha on the schedule recommended by standard veterinary practice. However, she came to believe that those vaccinations started the young Poodle's tidal wave of illnesses.
When Mocha was a year old, Alexander learned about the potentially adverse effects of vaccinations. In response, she embraced a holistic approach to wellness for her pets. She switched them to a home-prepared diet and found a homeopathic veterinarian. And she stopped vaccinating; instead, she had blood tests run to make sure that vaccinations given in the past continued to protect her dogs against life-threatening diseases. Mocha improved, and five years later, she's the picture of health. "I truly believe that if I had not made the changes I made for Mocha, especially saying 'no' to vaccines, she would not be here with me today," says Alexander.
Questioning Accepted Wisdom
Once the mainstay of responsible pet care, the practice of annual revaccination has come under scrutiny by the veterinary medical establishment. In 2003, the American Animal Hospital Association (AAHA), an international organization of companion-animal veterinarians, issued new guidelines for the vaccination of dogs. These guidelines divide diseases and their associated vaccines into three categories: "core," "non-core" and "not recommended." For the core diseases (distemper, parvovirus, adenovirus and rabies), they recommend revaccinating adult dogs no more than once every three years. "We need to move away from the idea that more is better when you're talking about vaccinations," says Link Welborn, DVM, past president of AAHA.
This is a significant departure from what was for decades standard practice for the responsible pet owner. The mentality used to be that repeated vaccinations might help, and couldn't hurt. But the mainstream veterinary community is now recognizing that the opposite is true: They don't help, and they might hurt.
"Unnecessary stimulation of the immune system does not result in enhanced disease resistance and may expose animals to unnecessary risks," reads the American Veterinary Medical Association (AVMA) Council of Biologic and Therapeutic Agents' 2002 report on cat and dog vaccines, which also pointed out that minimal scientific data support the practice of annual revaccination. Dr. Ronald Schultz, a veterinary immunologist at the University of Wisconsin-Madison School of Veterinary Medicine, puts it more simply. "For distemper, adenovirus and parvo, boosters really don't help. There's no benefit."
But there are risks. "Vaccines are potent, medically active agents and have the very real potential of producing adverse events," according to the AAHA's report. In addition to the potential for an immediate and life-threatening anaphylactic reaction, a connection is being made between repeated vaccinations and autoimmune diseases in dogs. Most vaccine reactions occur three to 45 days post-vaccination, says W. Jean Dodds, DVM, president of Hemopet and a leading researcher on vaccine issues. "The peak time is usually ten to twenty days," she says.
What kind of reactions are we talking about? Serious blood problems, seizures, high fevers, liver problems and polyarthritis (lameness that moves from leg to leg) are all vaccine-induced conditions seen by Dr. Dodds. She points out that most non-immediate reactions don't occur with the first dose of the vaccine. It's the subsequent booster, given to a dog who may have another as-yet-undetected disease process going on that tends to cause an adverse reaction, she says.
So, the bad news is that vaccinations can cause serious problems. The good news is that annual booster shots for the core diseases simply aren't necessary. If your dog has been successfully vaccinated in the past against these diseases, he's almost certainly still protected. Duration-of-immunity studies conducted by Dr. Schultz have found that vaccines for three of the four core canine diseases (parvo, distemper and adenovirus) are effective for at least seven years. Rabies, the only vaccination for which duration-of-immunity studies are required by law, has been shown to last at least three years. In addition, a study published in the January 2004 Journal of the American Veterinary Medical Association found that five common dog vaccines "lasted up to and beyond 48 months …." (It's conceivable that the effective spans are longer, but duration of immunity was only measured within the parameters of the study.)
For more than six years, the practice at UW-Madison's Veterinary Medicine Teaching Hospital has been to revaccinate dog and cat patients no more than once every three years. "We have not seen any evidence of vaccine-preventable diseases increasing," says Dr. Schultz, who since 1974 has been vaccinating his own pets on a very limited basis. He gives them puppy and kitten shots, then uses a blood test to check that their systems have produced antibodies in response to the vaccines. After that, he doesn't vaccinate them again, except for rabies as required by law.
Why the recommendation for shots every three years, if the data show the shots last much longer than that? It's a matter of acceptance by veterinarians. "The three-year interval is thought to be a reasonable compromise," says Dr. Welborn, who points out that the duration-of-immunity studies are very expensive, and therefore, the data available are limited. "We're not likely to have large-scale studies, ever."
Giving Boosters the Boot
If you're considering foregoing shots this year but are concerned that your pet might not be protected from the core infectious diseases, ask your veterinarian to run an antibody titer to find out. (Titers aren't useful for the non-core vaccines, whose duration of immunity is known not to exceed a year.) Titers should be processed at a laboratory that has properly validated its results, such as one of the large state diagnostic facilities like Cornell, Michigan State or Colorado, says Dr. Schultz. A reliable in-house titer test is now available for veterinary offices as well.
Though titers are frequently criticized for being unreliable, if they're run at a reputable lab, that unreliability is limited to false negatives. In other words, you can feel confident your dog is protected if a titer indicates he is. Dr. Schultz also points out that a low titer doesn't mean that your dog is unprotected. These tests measure only the antibodies circulating at the time the blood is drawn, not what's known as cell-mediated immunity, the so-called "memory" response. If your dog were exposed to the disease in question, the memory response would spring into action and protect him from becoming ill.
If your previously vaccinated dog's titer comes back low, consider that he may still be protected. Then, weigh his risk of contracting the disease against his risk of developing health problems as a result of the vaccination. Fortunately, most people don't have to make that difficult decision. According to research conducted by Dr. Dodds, titers indicate that approximately 95 percent of dogs and cats are protected from the core diseases after they've been properly vaccinated.
Puppies are protected from infectious diseases by antibodies passed to them by their mother through her milk. However, these maternal antibodies interfere with the baby animal's response to vaccines, and because it is not known when they wear off, puppies are usually given a series of shots, a few weeks apart, to ensure protection. The age at which a healthy puppy should given the first shot is open for discussion. "We're trying to take them as late as possible," says Dr. Dodds, who recommends a first distemper-parvo vaccination at the age of nine weeks, followed by another at 12 weeks, and a third at 16 to 20 weeks.
Vaccinations for non-core diseases-milder and/or geographically dispersed illnesses-should be evaluated on the basis of your dog's lifestyle. Bordatella (also known as kennel cough), for example, is an airborne disease that infects groups of dogs-a kind of canine cold. If your dog is never boarded or taken to classes, he doesn't need it. Bordatella is a self-limiting disease that is rarely serious in healthy dogs, so he may not need it even if he is boarded or in training classes. Lyme disease and leptospirosis are not seen in all geographic areas. It is up to you and your veterinarian to evaluate your individual dog's risk and decide about vaccinating. "The whole bottom line is a risk-benefit ratio," says Dr. Dodds. "What is the risk for this particular animal to [have] an adverse reaction, versus the risk for the disease in the area?"
Vaccines shouldn't be given to unhealthy dogs. Whether your dog is suffering from a short-term ailment or a chronic condition, give careful consideration before vaccinating. If he's had an anaphylactic reaction in the past, the AAHA report recommends avoiding revaccination. "The risk from vaccine-induced anaphylaxis may be much greater than the risk of infection."
Rabies is the only vaccination required by law in almost all states. (One exception is Florida, which has a "puppy lemon law" that requires commercially sold puppies to be vaccinated against a variety of diseases.) If your dog isn't healthy, you may be allowed to avoid the rabies vaccination by getting a veterinary waiver, depending on state law. However, that waiver may have no bearing if your dog bites someone or is bitten by a potentially rabid animal. Quarantine and revaccination may be imposed.
Boarding the Minimally Vaccinated Dog
Your veterinarian may tell you that your dog doesn't need annual shots, but your boarding kennel may well require them. What to do? Try to effect change through education. If your kennel requires proof of annual vaccinations for all diseases, talk with them about the vaccination schedule you and your vet have agreed upon, and emphasize that a one-size-fits-all approach isn't recommended by leading veterinary organizations. Ask if they accept titers. If they say no, call around until you find a place that does. Then call your preferred place back, tell them that other area kennels are accepting titers and see if that makes a difference. If it doesn't, consider switching kennels.
Another alternative is the petsitter. Hire someone to stay in your house with your dog, thus avoiding vaccination requirements altogether. The Web sites of the National Association of Professional Petsitters (www.petsitters.org) and Petsitters International (www.petsit.com) list member petsitters by locale. A less expensive option is to swap petsitting services with a friend whose dog gets along with yours.
Great Value, Zero Side Effects
Even if you never give your dog another shot, don't avoid your veterinarian-the annual vet visit isn't just for vaccinations. Just as with humans, the yearly physical helps spot problems early, when they're easier to address. "The annual exam is probably the most important part of preventive health care," says Dr. Welborn. "If you're going to give me a choice between vaccinating or doing a physical exam, I think the physical exam has the greatest value, because it provides an opportunity to assess multiple organ systems with one procedure. And it has zero side effects associated with it."
Both Dr. Schultz and Dr. Dodds emphasize that vaccinations should not be given up entirely. The key, says Dr. Schultz, is to vaccinate more animals less often. "If anything, I would like to see more animals vaccinated, especially with the core products, and individual animals vaccinated far less. I think we would accomplish a great deal more if we could get more dogs and cats vaccinated just once."
AAHA-recommended vaccinations for dogs
Highly recommended (core diseases/vaccinations):
Optional (non-core diseases/vaccinations):
Parainfluenza (when given in combination with the core vaccinations)
Not recommended for routine use:
Distemper-Measles (given to puppies only)