You may not be aware of it, but controversy over these questions is growing among breeders, veterinarians, and researchers. Some have attributed every ill of the canine and feline pet populations, from allergies to arthritis to severe immune system breakdowns, to excessive use of vaccines. Others, most notably vaccine manufacturers, insist the vaccines are harmless and that the benefits outweigh the risks.

Researchers, though, are now saying that the issue of the safety of annual re-vaccinations may not matter. Why not? Because for the most part, they say, booster shots are not necessary for common canine and feline viruses; immunity to these diseases lasts many years, or the life of the animal. And for some of the common bacterial diseases, immunity is so fleeting, and the side effects so numerous, that vaccination for these diseases may be useless and risky.

According to researcher Dr. Ronald Schultz, chairman of the Pathobiology Department at the University of Wisconsin School of Veterinary Medicine, "It is becoming increasingly more evident that it is no longer true to say, "Well, even if the vaccine doesn't help, it won't hurt." There are some canine vaccination programs that have no scientific justification that may have the potential of causing harm."

Schultz recommends a moderate approach to vaccination for dogs, eliminating some of the commonly given shots and reducing the frequency of the rest. He suggests evaluating the risk and benefit of vaccines on an individualized basis.

While Schultz's research did not include cats, Kirk's Current Veterinary Therapy XI states, "A practice that was started many years ago and that lacks scientific validity or verification is annual revaccinations. Almost without exception here is no immunologic requirement for annual revaccination. Immunity to viruses persists for years or for the life of the animal." "Canine and Feline Vaccines"; Philips, et al; 1994.)

How is the average pet owner to know what shots to give, and when? Most veterinarians, breeders, and animal shelter operators know only what the vaccine manufacturers tell them, and have an almost unquestioning belief that vaccines are lifesaving at best and at worst, benign. But pet owners can investigate canine and feline diseases and immunizations themselves, and with their veterinarians design a vaccination program specifically for the needs of their pets.

Dog Vaccines

The two most serious viral diseases to which dogs are susceptible are distemper and parvovirus. Distemper is an old, endemic canine disease, and in puppies often causes death. Parvovirus is an intestinal infection which first appeared in 1978, which also frequently causes death in puppies. Other diseases commonly included in dog vaccines are hepatitis, parainfluenza, corona, and leptospirosis. The vaccine for these diseases is called "DHLPP", or DHLPP-C when the coronavirus vaccine is included.

Distemper, parvovirus, and hepatitis vaccinations are extraordinarily effective, and according to Schultz, a single immunizing dose (which is not, he warns, the same thing as a single shot) should provide lifelong immunity. While Schultz says those who wish to take a more moderate approach can re-vaccinate adult dogs for these diseases every two or three years, he immunizes dogs with modified live virus vaccines for distemper, hepatitis, and parvovirus at six to eight weeks of age, and again at 14 to 16 weeks, with a last parvo vaccine at 22 weeks of age, and does not give any further vaccines.

Be sure, Schultz warns, that the vaccine used is an effective one; his study found brand differences in vaccine effectiveness as great as 100 percent. In other words, some vaccines are 100 percent effective at certain ages while at that same age others have no effect at all. According to his research, the most effective brands are Proguard and Duramune; the least effective brands are Galaxy, Adenomune, and RM.

Schultz also warns that the hepatitis component of the vaccine you use should be the one known as CAV-2; CAV-1, which is still widespread in commercially available vaccines, has been found to cause severe side effects. CAV-2 protects against both strains, one of which causes a liver infection and the other a respiratory disease.

Another vaccine which is becoming widely used is that for borreliosis, or Lyme disease. Lyme disease is a tick-born bacterial disease which in dogs causes a form of arthritis. Or at least, it may. Some researchers call canine Lyme disease "a vaccine in search of a disease", since it is actually unknown whether dogs even get Lyme disease. Dr. Christine Wilford, who is the veterinary columnist for the AKC Gazette, wrote, "In general, the efficacy of Lyme vaccination and the true incidence of the disease itself are still being debated by many specialists... (many of whom) still advise against using the vaccine, citing the absence of documentation of need and efficacy, and remind(ing) us that an effective human vaccine has yet to be developed." Neither Wilford nor Schultz recommend this vaccine.

Corona is a mild intestinal virus which usually causes no noticeable symptoms unless another intestinal infection is present as well. It can often be cultured out of the stool of healthy dogs. Schultz did extensive studies on coronaviruses. In his studies he concluded that corona is not a serious illness and that the vaccine is ineffective. (Schultz, "Emerging Issues: Vaccination Strategies for Canine Viral Enteritis": 1995.) He recommends against this vaccine, as does Wilford.

Parainfluenza is, by itself, a mild respiratory illness similar to a cold, but when complicated by bacterial infections can lead to pneumonia. The most common bacterial infections are those caused by bordetella, often erroneously called "kennel cough". Schultz recommends that while an injection is frequently used to vaccinate for these diseases, a nasally-administered combination of parainfluenza and bordetella should instead be given at six to eight weeks and again at 14 to 16 weeks, with annual nasal boosters of the bordetella alone for dogs at high risk of contracting the disease (show dogs, dogs in boarding kennels, etc.) The parainfluenza vaccine, like those for parvo, distemper, and hepatitis, should provide longer term immunity, probably lifelong. Bordetella, like all bacterial vaccines, requires more frequent administration.

Cat Vaccines

Schultz's research did not include feline vaccines, but many holistic vets and breeders recommend cats be immunized every five years for feline panleukopenia, also known as feline distemper, and no other diseases. Others recommend that feline rhinotracheitis also be included. Feral cat colony caretakers have anecdotally observed that the cats do remain immune to common feline diseases throughout their lives despite only having been vaccinated once, but my research did not uncover any definitive studies.

Cat breeders and holistic vets alike have assembled many horror stories about the ill effects of the feline leukemia (FeLV), feline calicivirus, and the new feline infectious peritonitis (FIP) vaccines. In researching this article I read a paper by Lorraine Shelton, an immunology researcher working with the FeLV and FIP vaccines, which offered substantiation for the anecdotal evidence gathered by breeders and holistic veterinarians. Her paper has been the cause of substantial controversy, and while she has extensively documented her sources, some veterinarians disagree with her conclusions. Her paper is reprinted in the January/February 1995 issue of Natural Pet magazine for those who would like to know more.

The most troublesome of the feline vaccines seem to be those for feline leukemia, feline infectious peritonitis, and calicivirus. Many cat breeders do not use these vaccines.

I did not find as much information about cat vaccines as about dog vaccines, and so cannot offer as much information as cat owners might like. The Winn Feline Foundation is currently sponsoring research into feline vaccines, most notably into the connection between vaccines and fibrosarcoma, a form of cancer. Those interested in this subject can subscribe to the Cat Fanciers' Almanac, which reports on the results of Winn Foundation research. Their number is (908)528-9797.

What You Can Do

The average pet owner can become a smart consumer. Don't just blindly buy whatever vaccines the clinic or veterinarian is selling. Ask how severe and how prevalent in your area are the diseases for which vaccinations are being suggested. What about the effectiveness of the vaccine, and its side effects? If a disease is both not serious and not prevalent, it may be better not to vaccinate against it, particularly if the vaccine is either ineffective or dangerous, or both. Ask your veterinarian to customize your pets' immunizations in light of new information on safety and efficacy, and to update the immunization program as new research is done. Remember: when it comes to health care decisions, one size really never fits all.

Copyright 1997 the author. All rights reserved.