Every once in a while someone will start a discussion on vaccine efficacy, and risks associated with vaccination. The latest discussion is in regards to a veterinarian in Connecticut, Dr. John Robb, who after a 4 year battle with regulators, was given veterinary license probation. He is not allowed to vaccinate any animal for rabies for 25 years. In addition, for the next 18 months, he must practice under the supervision of a colleague who has been approved by the state board regulatory agency.
The reason for his censure revolves around the question of dose size of rabies vaccine in respect to the size of the animal. For example, should a Chihuahua get the same size rabies vaccine as a Great Dane? The common sense answer would seem to be “no”. However most immunologists and veterinarians who understand immunology would disagree. Why? Dr. Ronald Shultz, longtime researcher of vaccines at Wisconsin-Madison School of Veterinary Medicine, discussed this topic in the Journal of Small Animal Practice. “Unlike pharmaceuticals that are dose-dependent, vaccines are not based on volume per body mass (size), but rather on the minimum immunizing dose. “ Dozens of years of research has determined pets need a certain minimum amount of rabies vaccine to stimulate the immune system to protect against disease. The immune system of a small dog and a large dog need the same size dose in order to tell the immune system “Hey! There is a virus here! Let’s protect against this.” In fact, if the Chihuahua has a poor immune system he may need a larger amount of vaccine to obtain the same level of protection as the Great Dane. If one were to give a lesser amount of rabies vaccine there is a valid concern the immune system may not be stimulated enough to protect against future exposure to the virus.
Think about that….Think about that very seriously….Imagine your child or grandchild is bitten by a dog that has been vaccinated against rabies inappropriately and has not developed a good immune response to prevent rabies. Now, imagine that dog bit your child/grandchild after getting in a fight with a skunk, raccoon, or other rabies reservoir species, such as a bat or coyote, which no one knew about. You take your child/grandchild to the doctor. He asks if the dog was vaccinated. The answer is “yes”. Your doctor is now no longer worried about the risk of rabies because the vaccine is so effective when given in accordance with regulatory guidelines. He does not recommend treatment against possible rabies exposure. Your child/grandchild contracts rabies from the bite. Rabies is almost 100% fatal once clinical signs develop. Many people fail to understand, while rabies vaccine protects animals, the reasons the UDSA rules and the state laws are there are to ensure rabies vaccine given to pets protect the people around those pets.
Dr. Robb is concerned about vaccine reactions of all types: anaphylaxis, serum sickness, immune mediated disease, death. Granted any vaccine, or honestly any drug, could cause these reactions. We do see vaccine and drug reactions. Thankfully, they are not common and usually are treated and prevented without significant difficulty. Some, however, can be very difficult to treat and while I have never had a patient die from a vaccine, I know it may happen sometime in my career. However, I do not believe by reducing dose size I will prevent or reduce the risk of any of these reactions. Think about a peanut allergy. An allergic response to peanuts is the immune system over reacting in an inappropriate manner. Do you believe the size of the peanut dose really matters? How many times have you heard of someone having a peanut allergic response to a product that was made in a facility with peanuts though there were no peanuts in the product? If your immune system is going to overreact, dose size may not be a factor.
There are many other concerns out there regarding vaccines, in addition to rabies vaccine dosing size, such as titers, dosing interval, types of vaccines, adjuvant in vaccines, area of body to vaccinate, different serovars of vaccines, etc. There is also extensive debate among veterinarians, specialists, researchers, the USDA, and state regulatory bodies regarding these concerns. Unfortunately, for many of these concerns no one knows the appropriate answer. Until we have actual proven scientific data backed up by extensive testing we have to go with what has been proven to protect our pets and our families. I will continue to use rabies vaccines at the labeled dosing and at the dosing interval recommended by the State of Michigan Board of Veterinary Medicine.
Jeff Pinkston D.V.M