March 31, 2015

Rabies Challenge Fund: Five-Year DOI Study Results

It seemed a long uphill climb for the Rabies Challenge Fund in 2005 when it formed a 501(c)3 organization to privately fund a rabies vaccine duration of immunity study.

Rabies vaccine manufacturers would not take on the challenge; a study longer than three years "cost too much." The USDA, the body that regulates animal drugs, would not accept serum-based immunological studies that have demonstrated that rabies vaccine has a much longer duration of immunity than three years.

Rabies vaccine has been demonstrated to have a minimum duration of immunity of
seven years by serology by Dr Ron Schultz, and 4 years for cats and 5 years for dogs
by challenge by Aubert. Aubert’s study shows that the chances of a dog or cat
developing rabies in the United States that has had one rabies vaccination is less than one in eight million, (1:8 million)
Refs: Schultz, Ronald D, Duration of Immunity to Canine Vaccines: What We Know and What We Don’t Know, Proceedings – Canine Infectious Diseases: From Clinics to Molecular Pathogenesis, Ithaca, NY, 1999, 22
Aubert Michel F, The practical significance of rabies antibodies in cats and dogs, Scientific and Technical Revue, 11(3) 735, 1992 Paris, France
For pet owners who had experienced the loss of beloved dogs and cats because of adverse reactions to repeat rabies inoculations, the only solution was to fund the study for ourselves.

And so we have.

Ten years downstream, results are beginning to emerge.
Our conclusion from studies with the initial rabies vaccine is that the immunity conferred by that product, and assessed by the in vitro RFFIT, was excellent for the first three years, then declined during the fourth year, and continued to drop during the fifth. Nevertheless, the dogs that completed the five-year study who were given a second rabies vaccine (even those with rabies antibody titers that dropped below the RFFIT positive level), demonstrated boosted rabies titers, indicating the presence of an active immune memory cell response. The second vaccine group, which is now three years from vaccination, will remain on study for at least two more years.

Read more here.

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