Are changes in the wind?

Introduction

For generations of pets, the annual booster vaccination has become a ritual Fido goes to the clinic to get his inoculations and an exam that is considered a byproduct of the shot visit by many owners.

These days, for convenience and budgets, some owners forego the exam and take Fido or Fluffy to a pet supply store for a jab of protection against rabies, distemper, parvovirus, and other canine diseases.

But things may be changing. Veterinarians at the Ohio Veterinary Medical Association conference in February said that research shows that vaccines have a longer term of effectiveness against disease than previously thought, and some veterinary colleges have published alternative vaccination protocols that suggest three-year intervals after the initial shots and a 12-month booster. Some veterinarians go further; they recommend skipping vaccinations altogether for older animals that seldom leave home.

The change may be a welcome one, but it can have hidden dangers if pet owners forego the annual exam as a result. Fido needs that checkup even if he is fully protected against disease by last years vaccination.

Why the switch?

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, said the announcement of a new vaccination protocol at the Colorado State University Veterinary Teaching Hospital. Boosters, the annual re-vaccination recommendation on the vaccine label is just that a recommendation, and is not a legal requirement except for rabies. This recommendation could just as well have been every leap year or full moon and is not, in most cases, based on duration of immunity studies.

The recommendation for annual boosters came from the drug companies, according to veterinarians at the OVMA conference. The only vaccine for which duration of immunity studies is required is rabies vaccine; few studies have been done to pinpoint the length of protection offered by distemper, parvovirus, and other vaccines to determine if boosters should be given at greater or lesser intervals.

So why vaccinate?

Although there is a growing concern over vaccine frequency, there is no doubt that vaccines control diseases that can kill puppies and dogs and protect individual dogs from illness and death.

According to an article in the Journal of the American Veterinary Medical Association in 1995, concerns center on the potential for vaccines to trigger autoimmune diseases in susceptible dogs and the necessity for annual boosters. Data is scant, but suspicion is growing, according to Dr. Ronald D. Schultz of the University of Wisconsin Department of Pathobiological Sciences.

I am a strong advocate of vaccine use, Dr. Schultz said in the JAVMA article. We need to strike a balance between those who feel that no vaccines should be given and those who are vaccinating every week. Annual vaccination has become a knee-jerk response that, for the most part, is unnecessary. We have come a long way in reducing disease through vaccination, but perhaps we have gone too far.

How vaccines work

Vaccines stimulate the immune system to produce antibodies to the disease so that the dog is protected against various organisms in the environment. If the immunized dog is later exposed to the infectious agent, the antibodies react quickly to attack and destroy the disease.

Initial shots are given to puppies to gradually phase-in immunity as the mothers milk protection wears off. Puppies are generally vaccinated against parvovirus, distemper, adenovirus (vaccine also protects against hepatitis), and parainfluenza in combined shots and against rabies. They may also be vaccinated against leptospirosis, Lyme disease, and corona virus if local conditions warrant or if the pet will be traveling in an area where these diseases are known to be a problem.

Vaccines come in two types: killed virus or bacterin and modified live virus or bacterin. The killed vaccines are mixed with an adjuvant to boost the effectiveness, and various adjuvants are suspected of causing problems. Killed vaccines are more stable, but they require more injections to immunize the pet and are more likely to cause allergic reactions ranging from low-grade fever or muscle aches to hives, facial swelling, or even vomiting and diarrhea. In rare cases, a pet may collapse within a few minutes of the injection from a severe anaphylactic reaction, but most reactions take a day or more to manifest.

Modified live vaccines work more quickly and for longer periods, are less expensive, and require only a single dose to be effective. However, they should not be used in sick animals and may cause suppression of the immune system in susceptible animals or abortions in pregnant bitches.

Vaccinations challenge the immune system in a complex manner, so it is not advisable to vaccinate a puppy or dog that is sick. Vaccines can fail if the animal has a fever or is taking steroids, or if they are given too close together or too far apart. They can also fail if the vaccine has been improperly handled or stored and may not protect a puppy that has lost immunity from mothers milk before the vaccine is administered.

Despite problems, vaccinations are still a pet owners best line of defense against distemper and parvovirus that can kill puppies and young dogs, against rabies that will kill dogs and people of any age, and against other contagious diseases that can cause short term and long term health problems.

Pet owners should work with their veterinarian to design a vaccination schedule for each pet based on age, health status, reproductive status, and environment. Rotating vaccines so that they are not all given at once is one option, and titer tests for antibodies is another. However, titer tests are more expensive than vaccinations and not completely reliable, so many vets do not recommend them.

If owners do vaccinate a pet and he has a reaction, it should be reported to the veterinarian and the US Pharmacopeia, a private organization that operates a reporting program in conjunction with the American Veterinary Medical Association. USP can be reached at www.usp.org on the world wide web or at (800) 487-7776.

If pet owners and their veterinarians decide that other than an annual vaccination is appropriate for particular pets, owners should get a veterinary statement to that effect if questioned at a grooming shop, boarding kennel, or training school. Those who plan to board pets should get the intranasal Bordatella vaccine at least two weeks before vacation dates, for this vaccine has a shorter period of effectiveness than parvo or distemper vaccines.

Annual exams

Annual boosters for Fido and Fluffy is really shorthand for yearly checkup. The veterinarian does far more than inject the vaccine; he listens to heart and lungs, probes belly, looks at teeth and gums, examines eyes and ears, checks for parasites and skin disorders, asks questions, watches the dog move. He discusses ideal weight and exercise if necessary, and listens to questions and concerns of the owner. Dogs that visit the veterinarian once a year live longer and are less likely to be surrendered to a shelter because the owner has an animal health professional to answer questions and to find potential problems before they become serious. Shot clinics in pet supply stores do not provide these opportunities.

Homeopathic remedies an alternative to vaccines?

Herbal and homeopathic remedies and treatments such as acupuncture and chiropractic are gaining popularity as alternatives to modern medicine for people and pets, but it is highly unlikely that anything in this assortment of alternative remedies will replace vaccinations against canine and feline diseases. Homeopathic nosodes have been used as a vaccine substitute and credited with preventing these diseases, but there are no studies that support their use on a broad scale and no quality assurance in their production.

Susan Gayle Wynn, DVM, said on the Alternative Veterinary Medicine website (AltVetMed Vaccination Decisions) that . . . unfortunately, there is no convincing evidence that nosodes do prevent disease. A few studies published in homeopathic journals suggest that nosodes may decrease the severity of active disease and possibly prevent the spread of epidemics, but these studies are not well-controlled.

Wynn, a homeopathic veterinarian, continued: The results of one well-controlled study suggest that parvovirus nosodes are completely ineffective in preventing parvoviral disease under experimental challenge conditions. Until well-designed studies are completed and thousands of pet owners make a concerted effort to help with potential retrospective studies, nosodes remain an unknown quantity and I do not recommend using them as a sole strategy for disease prevention.

Dr. Wynn recommends puppy and kitten vaccinations followed by annual boosters for a year or two.

Nosodes

Homeopathy was developed in the late 1700s by German physician Samuel Hahnemann, who proposed that small doses of a substance could prevent or cure diseases caused by large doses of the same substance. This is the same principle behind the development of vaccines. However, nosodes are produced according to Hahnemanns law of infinitesimals, a technique that dilutes the original substance beyond recognition, leaving no recognizable traces of the original substance and no measurable protection in the animals body.