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Question:
I have read your recommendations about vaccines. I just heard about a friend's dog that got rabies, even though the dog had been vaccinated 8 months ago. Now, I read in the newspaper that there is a rabies epidemic in our area, in wildlife. Should I go get another vaccine as my local veterinarian suggested, even though my dog was given a three-year vaccine 1 year ago?
Answer:
I have run at least 70 rabies titers (a test to determine if the rabies inoculation is effective) over the years. All have come back protective (the titer shows that the immune system is protected against rabies for most animals), with one exception. That one exception was in a cat for which the owner requested a "proportional dose" be given and then tested. I gave the cat a 0.1 cc dose of rabies vaccine. I normally would not do this, but the cat was to be sent to England and would have to be titer tested prior to traveling, anyway. I thought it would be a good test case for proportional dosing. Titer testing indicated that the cat did not have a protective dose. We gave the full dose, and the second test was fine. Take from that what you will - only a more controlled, detailed study would determine why the dosing was not effective - but this cat did not respond to 0.1 cc rabies vaccine. Still, I do not do proportional dosing of any vaccine in puppies and kittens, and I don't do it with rabies vaccine for animals of any age.
From my previous training in epidemiology (the study of diseases and how they spread), I was taught this: the rabies vaccine is never 100% effective. The factors that are in play include:
1. The amount of rabies virus in the saliva of the infected animal
2. The location of the bite - the closer to the head the higher the risk of infection, and into a blood vessel is the worst bite of all
3. The obscure: concurrent diseases or a compromised immune system
4. It is generally accepted that the vaccine in dogs seems to be about 95% protective. Thus, in my mind, it is a "good" vaccine, meaning it works. It seems to protect better in cats (who have better natural immunity anyway) and not as good in other species (your got it, those that are more susceptible by nature), although that gets even harder to know for obvious reasons.
5. The level of rabies in domestic animals is not a function of frequency of vaccination, it is a function of the percent of the dog/cat population vaccinated (meaning has it ever been vaccinated) at any one time and the level of endemic rabies in native wildlife.
Many state health department enforcers (veterinary epidemiologists) believe that any cat or dog that has a history of rabies vaccine that includes at least two shots is as well protected as ones that get yearly vaccines. And, an animal that has been vaccinated once, and no more than 1-2 years has passed since that vaccine, is as well protected as an animal on any other vaccine regime. Of course, that is "off the record", as they are not likely to say anything other than that the animal needs rabies vaccines as required by the laws of the state they serve.
My opinion (excluding rabies, which is legally required and filled with human health complications) is this: All vaccines, once given, are either protective for life or should not be given to start with in almost all situations - e.g. Bordatella. Vaccine failures will sometimes occur. The failure rate of FeLV (Feline Leukemia Vaccine) is so high that natural immunity is vastly more protective. So, with the potential for vaccine-related sarcoma's (cancers) I do not believe in that vaccine. Since failure is a common event, we fall into the false believe that "if only we would have vaccinated more frequently, the animal would be fine today." The case in question is a good example of that: the rabies vaccine is not required to be boosted until one year later, and there was a vaccine given, timed so that it should have worked.
The problem with deciding about vaccines is entirely fear-based thinking. Fear of loss of income, fear of lawsuit if an animal gets a disease we did not vaccinate for, owner fear of the unknown, etc.
Remove the fear factor and we are left with an easy decision about vaccines. As Dr. Schult, a prominent expert in animal vaccines, said over 10 years ago in Current Veterinary Therapy, viral vaccines last for life (or the animal doesn't respond, period, and it does not matter how many more vaccines you give). When you add in the fact that animals are healthier when vaccines are kept to a minimum, including a healthier immune system, I am left to conclude the following about vaccines in dogs and cats. We should, as a general rule, vaccinate:
1. as puppies and kittens, but not in adult dogs and cats
2. only for life threatening diseases
3. for rabies as required by law - check with your state's health department for vaccine requirements in your area