FDA to hold public smallpox vaccine workshop

The U.S. Food and Drug Administration will co-host a public workshop on Sept. 16 about the evaluation and development of next generation smallpox vaccines.
The FDA's Center for Biologics Evaluation and Research and the National Institute of Allergy and Infectious Disease will co-host the event at the Hilton Washington D.C. North/Gaithersburg in Gaithersburg, Md. It will include presentations on the development of animal models for demonstrating vaccine effectiveness and human response to smallpox vaccines.
While the World Health Organization declared smallpox eradicated in 1980, the FDA says the threat of smallpox as a biological weapon remains. First-generation smallpox vaccines were prepared in chicken eggs or on the skin of calves or other animals.
"Although these vaccines were not evaluated for efficacy in well-controlled trials, they were highly effective as evidenced by the successful global eradication of smallpox," the FDA said. "Manufacturing of these vaccines has ceased and they are no longer licensed in the United States."
The FDA licensed the first second generation smallpox vaccine, ACAM2000, in 2007. The vaccine is aseptically propagated using cell culture technology under modern manufacturing standards and practices.
"Because ACAM2000 may cause serious adverse reactions, there is a desire to develop safer vaccines should there be a need to vaccinate the general population due to a threat of an attack with the smallpox virus," the FDA said. "Currently, the next-generation smallpox vaccines under development do not produce the characteristic 'vaccine take.' In addition, it is not ethical or feasible to evaluate the effectiveness of these vaccines in humans as the natural disease has been eradicated. Therefore, the effectiveness of these next-generation smallpox vaccines may be based on animal efficacy data, if scientifically appropriate, and to comparative human immune response data. As for any biologic product, licensure of new smallpox vaccines requires demonstration of safety, purity, and potency."
The workshop will discuss regulatory challenges and strengths and weaknesses of various animal models that can be used to predict effectiveness.