June 21, 2009

Rabies Vaccinations - Why Less Is More

Yesterday, I exchanged emails with a reporter in Dothan, Alabama about coverage of confirmed rabies cases in Houston County in the raccoon population.

The author reported the admonition of a local public health offical to vaccinate pets against rabies; however, the article perpetuates the myth that annual rabies vaccination is both necessary and good, when it is anything but.

[Dothan, Alabama] Health officials are warning residents to stay alert and make sure their pets are vaccinated.
Public Health Environmentalist Keith Hicks said, "The health department advises children not to handle a stray pet or unwanted animal. We do like to ask residents to have their pets vaccinated each year."

That annual rabies vaccine helps to not only protect your pets, but also to create a barrier between you and rabid animals.

Hicks said, "Your pets act as a buffer between the wild and humans so it is important to have your animals vaccinated annually."

I get a little crazy when read these stories.

The whole point of mandatory vaccination of companion animals against rabies is to protect the public from rabies outbreaks by virtue of "herd immunity." In simple terms, the more domestic animals that are vaccinated, the lower the risk of rabies transmission from rabid coons, skunks and bats to dogs and cats and the safer their humans.

The proportion of vaccinated pets necessary for herd immunity can be quantified.

In a study of Transmission Dynamics and Prospects for the Elimination of Canine Rabies, researchers established a statistical model for herd immunity in eradicating rabies:

There were no rabies outbreaks (defined as at least two cases not interrupted by an interval of more than one month) in villages when vaccination coverage exceeded >70%. Small outbreaks occurred in villages with lower coverage and the largest (and longest) outbreaks only occurred in villages with <20%>

According to this study, a rabid dog will bite 2.5 other creatures. If three out of four of these is immune to rabies virus, the risks of transmission to the human population is reduced exponentially.

So isn't the total number of family pets that are vaccinated against rabies more significant than the number of rabies shots given to any one animal?

The veterinary professionals who write "the Bible" for rabies prevention and control laws think so.

According to the National Association of State Public Health Veterinarians (NASPHV), the most effective way to ensure compliance with rabies laws is to extend the interval to at least three years.

The Center for Disease Control’s National Association of State Public Health Veterinarian's (NASPHV) Compendium of Animal Rabies Prevention and Control 2008 states that, “Vaccines used in state and local rabies control programs should have at least a 3-year duration of immunity. This constitutes the most effective method of increasing the proportion of immunized dogs and cats in any population (50).” They specifically warn that, “[n]o laboratory or epidemiologic data exist to support the annual or biennial administration of 3- or 4-year vaccines following the initial series.” Also endorsing the NASPHV’s Rabies Compendium are the American Veterinary Medical Association (AVMA)[1] and the American Animal Hospital Association (AAHA).

This suggests that at a certain point, stringent rabies laws are ineffective; for cost or personal reasons, people won't vaccinate their dogs and cats. It also states - without exception - that the practice of annual rabies shots has no medical basis.

Sadly, in 2009, we must protect our companion animals from public health officials who have not updated their knowledge of the subject since 1950.

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