Why Annual Pet Vaccinations Still Make Sense

Dr. John Ellis is a professor of Veterinary Microbiology at the University of Saskatchewan’s Western College of Veterinary Medicine and a well-known expert on vaccine safety and efficacy.

Lea-Ann Germinder, executive editor of Goodnewsforpets.com, recently talked with Dr. Ellis about the debate surrounding new vaccine protocols for dogs and cats. To set up an interview with Dr. Ellis or for additional resource material, email Lea-Ann Germinder at lgerminder@germinder.com or call 816-822-0192.

Germinder: What’s your position on the debate surrounding the new vaccine protocols?

Dr. John Ellis

Ellis: I think the one incontrovertible fact or observation in the vaccine debate is that there is a very strong association between the recommendation for annual vaccination and a dramatic reduction in the incidence of infectious disease in companion animals. Essentially, annual vaccinations and wellness exams have gotten us to the point where we are now in veterinary medicine, which is a dramatic reduction in the prevalence of devastating infectious diseases in companion animals. So from a scientific perspective, the annual vaccination is the gold standard against which all changes in vaccine protocol must be considered.

Germinder: Do we risk a renewed rise in infectious diseases if we move away from annual vaccinations?

Ellis: The real issue is: What frequency of vaccination is most effective? Do we achieve better clinical immunity by vaccinating more frequently? That’s the central hypothesis that really needs to be tested in this debate.

Germinder: Are regular pet vaccinations important for human as well as animal health?

Ellis: Not only are we attempting to protect the individual animal and pet populations, but more importantly, in some cases, we’re attempting to protect the human population from the transmission of zoonotic infections, such as Rabies or Bordetella, and maybe Borrelia (Lyme disease). If we have a better overall herd immunity within the pet population, we’re less likely to have disease transmission to the owner.

Germinder: There have been some in academia who have suggested that they’re not concerned about the coronavirus coming back, because if it does, all it will mean is that the pet will get sick. What are your thoughts on that?

Ellis: Well, as veterinarians, I think it is our job, not only to prevent fatal diseases, but also to reduce illness due to a whole variety of agents. And, reduction in illness is best accomplished through prevention, not treatment, particularly at the time when there’s increasing concern about the over-use of antibiotics. Coronavirus, is an example of a usually nonfatal infection that affects primarily puppies, causing diarrhea. Minimally, I think we should consider vaccinating all bitches prior to breeding, or during pregnancy to maximize the transfer of maternal antibodies in the colostrum and thereby provide passive protection for the puppies.

In fact, coronavirus vaccination of cows is often done to reduce the effects of bovine coronavirus infections in calves. As well, we should not forget that many pathogens, including coronaviruses, can be associated with more than one type of disease. As you know, coronavirus has been associated with respiratory disease in pigs, cattle and humans, and it wouldn’t be surprising if it were associated with respiratory disease in dogs, especially in kennel situations. I think that issue needs further investigation.

Germinder: Some have suggested serological studies demonstrate that annual vaccinations are unnecessary. Is that a valid conclusion?

Ellis: There are a number of problems associated with serological testing. One is that there’s been virtually no standardization in the veterinary profession with regard to conducting these tests. Without any standard protocols or standard interpretation, it becomes very difficult to decide scientifically exactly what the measurement of antibodies or titers mean.

In addition, most of the serological studies have been conducted in relatively small populations of animals. Basing recommendations on a serological examination of a relatively small population of animals is somewhat naïve. With regard to human health issues, for example, the medical profession has vastly more data on which to base their recommendations or changes in treatment protocols.

Germinder: So safety is the key issue?

Ellis: Absolutely. If we have controlled or reduced the prevalence and incidence of infectious disease through the recommendation for annual vaccination, if we have something that works, why are we fixing it or changing it? Especially, since there are uncommon or rare adverse reactions associated with this practice.

Germinder: Are you saying that the science isn’t there yet to support a three-year vaccine protocol?

Ellis: I don’t think there is any easy answer to that question. Certainly in human medicine, with the resources and the infrastructure that exist, it’s much easier to draw firm conclusions than in veterinary medicine. I don’t think it’s reasonable to extrapolate between human beings and companion animals with regard to duration of immunity following vaccination for a whole variety of reasons, including differences in exposure to infectious agents, differences in population densities, and differences in disease causing agents and vaccines.

Unfortunately, in veterinary medicine, we may never get to the point where we have the amount and quality of data that our colleagues in human medicine have, it’s probably that simple. This would require epidemiological studies on large populations of pets to determine the true duration of clinical immunity following vaccination. The only way such studies would be possible would be if there was a concerted effort involving the professional organizations, such as the American Veterinary Medical Association, the federal and state regulatory agencies, practicing veterinarians, vaccine manufacturers, and, importantly, pet owners. The question is: who would lead and organize such an effort? It would be a daunting task.

Germinder: Have you looked at the data regarding the incidence of sarcomas?

Ellis: The data indicate that the prevalence and incidence of this particular problem is very low. The key question is whether the frequency of sarcomas would actually be reduced if we altered the vaccination protocols. I don’t think we can definitively say that sarcomas are solely the result of vaccination, by any means. In fact, it is probably more correct to say that some sort of genetic predisposition in the individual animal is the critical determining factor that leads to the development of a tumor following an inflammatory event such as vaccination.

If, for instance, one compares the amount of vaccination that is done to the prevalence of adverse reactions of any type, then one of the obvious conclusions is that, in fact, those animals that do have problems are in some way genetically predisposed to have those problems.

This is another area in which definitive answers will probably be a long time in coming. Think of it this way: It’s been over 30 years since “war” was declared on human cancer. Millions of dollars have been spent. Thousands of bright scientists have worked countless hours. And, we are only now beginning to understand the genetic links to only some cancers. Unfortunately, I think we are a long way from that in veterinary medicine, mainly because we simply don’t have the same resources.

Germinder: Thank you, Dr. Ellis.

To set up an interview with Dr. Ellis or for additional resource material, email Lea-Ann Germinder at lgerminder@germinder.com or call 816-822-0192.


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