Anti-Vaccine Trend May Threaten All Our Pets


Dr. Michael Paul authors this guest blog. Dr. Paul is a past president of the American Animal Hospital Association, past CEO and president Companion Animal Parasite Council and currently president MAGPIE Veterinary Consulting.  He also twice chaired AAHA Vaccine Guidelines Task Force and was a participant Joint AAHA/AVMA Pet Preventive Healthcare Guidelines Task Force. Here he comments on vaccines, and recent concerns. 

No medical development has had a greater impact on the prevention of diseases and general health of people and animals than the development of vaccines against various diseases.

Currently, vaccinations have become a controversial issue in human health, and increasingly the same has occurred in animal health.. Many of the diseases that health officials, from individual physicians to the CDC recommend vaccination against have been so successfully controled that most of the general public has never experienced or even seen the nightmare of some of these diseases. Smallpox has been eliminated and Polio is now extremely uncommon in the U.S..

The purpose of this commentary is not to respond to the controversy surrounding childhood vaccinations and their advantages and disadvantages. The vaccination of children is a critical decision that should be made only with the input of a physician you trust. I am not a physician and while I have a strong personal opinion about childhood vaccination, I am not qualified to debate the issues of childhood immunization.

On the other hand, I am a veterinarian with a history of involvement in national Task Forces established to review scientific studies and commentaries and to recommend specific vaccination protocols for dogs and cats. I have seen and treated infectious diseases in a clinical setting since 1972.  As a young boy I can recall several of my pets developing severe illnesses that in retrospect were probably canine and feline distemper. Both of these generally fatal diseases that were once common are now so uncommon that many veterinarians may never have seen a case.

.Today, as a rule, outbreaks of feline and canine distemper are limited to shelters or communities where pets may not be adequately vaccinated.

Rabies, a deadly disease of animals and humans is easily prevented and though still seen it is seen in non-vaccinated animals that have been exposed to infected wildlife. . When I was a young veterinarian these diseases were common. Infectious Canine Hepatitis was wide spread. Canine Parvovirus emerged in 1976 in Europe. It spread worldwide in 1978 killing countless dogs. Initially there was no vaccine available and infection was often fatal. At one time Rabies infection was common and not only invariably fatal but a significant risk to humans as well.

Over the years, since I entered the profession in the early 70’s more effective safer vaccines have been developed against these diseases and they have been widely used to a point where most pets have been vaccinated to at least some degree. As a result most pet ownners and many veterinarians have not seen these diseases.

Clearly not every dog and cat has been vaccinated and yet most pets spend their lives free of diseases that once plagued dogs and cats. Why is the general population protected when we know that many animals remain unvaccinated?

In part this has been due to a phenomenon sometimes referred to as “street acquired immunity” wherein individuals are exposed to infectious organisms at low levels or to weakened organisms capable of infecting but not producing fatal infection. Think of the times we all experience colds and viruses of varying severity from mild to severe.

In addition there is the concept known as “herd health” or “population immunity” wherein if a critical mass of individuals are immunized the disease is less likely to spread. Veterinarians and other healthcare professionals are familiar with the concept and the fact that if we can maintain immunity in about 70 percent of a population, the virus in question will not spread as rapidly or widely as in a population that is largely susceptible as occurs when  vaccines aren’t being used). Non immune individuals are still at risk for infection but an unvaccinated individual is less likely to be exposed and infected provided the population at large is immune. Massive outbreaks or epidemics are avoided because most individuals are immune.

This is where the reluctance of individuals to vaccinate their pets, or for that matter their children, increases the risk of infection among the herd or society. Granted, not every vaccinated individual will be fully protected and not every exposed but not vaccinated individual will become fatally ill, and if they recover they will have immunity against the disease. However many individuals will spread the disease among other susceptible individuals. So not vaccinating an individual pet places them at risk but also increases the risk to others. Should the percentage of unvaccinated individuals drop below a herd protective level of 70 percent,  now brace yourself as epidemic transmission may occur.

I am very much a libertarian when it comes to individual choices and if you choose not to immunize your pet or for that matter your children, that is your choice to make. While I may find the decision hard to endorse, I support your right to make the decision for yourself, your family and your pets…to a point.

Failure to immunize an individual may be unwise and put an individual at risk while advocacy against vaccination puts the “herd” at risk and greatly increases the potential for disease epidemics in pets as well as in people.

All of us have a right and a responsibility to make individual medical decisions but advocating against immunization places entire populations, not just individuals, at risk.

It is important that pet owners become informed and critical consumers of health care. The decision whether to immunize or not should not be taken lightly and should be made only after a discussion with your health-care provider and expert input. Decisions about health are not ever to be taken lightly nor made based on input from self appointed authority opinions.

HERE are the Canine Vaccine Guidelines from the American Animal Hospital Association

HERE are the feline Vaccine Guidelines from the American Association of Feline Practitioners.