Thompson's senior science adviser, Donald Ainslie (D.A.) Henderson, the physician and epidemiologist who oversaw the World Health Organization's successful campaign to eradicate smallpox from the world in the late 1970s, served as a consultant to the committee, known as the Smallpox Modeling Working Group. The group was convened by the Secretary's Advisory Council on Public Health Preparedness, a branch of the U.S. Department of Health and Human Services.

"Earlier studies recommended mass pre-vaccination of the general population to protect against a smallpox attack. None of us on the committee believed this was necessary, including D.A. Henderson, who intimately understands the natural history of the virus," Longini said. "The secretary of Health and Human Services wanted to settle such issues regarding smallpox containment once and for all, and this was our charge."

While the researchers did find that mass vaccination would slightly reduce the number of deaths from smallpox, they also found that the rate of severe illness and death caused by the vaccine itself would cancel out any benefit from mass vaccination. One person in 10,000 will have a severe reaction and one in a million will die from the vaccine, Longini said.

"Precautionary vaccination of hospital personnel and post-release vaccination of the target population would further contain the spread of smallpox, but at a cost of many more people being vaccinated," said co-author and Hutchinson Center biostatistician M. Elizabeth (Betz) Halloran, M.D., D.Sc. "The financial cost and potential illness and death related to vaccination must be weighed against the potential benefits in the event of an attack. In our opinion, pre-vaccination of the population at
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Contact: Kristen Woodward
kwoodwar@fhcrc.org
206-667-5095
Fred Hutchinson Cancer Research Center
16-Oct-2006