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Modeling the Optimum Duration of Antibiotic Prophylaxis in an Anthrax Outbreak
Proceedings of the National Academy of Sciences (2003)
  • Ron Brookmeyer, Johns Hopkins Bloomberg School of Public Health
  • Elizabeth Johnson, Johns Hopkins University
  • Robert Bollinger, Johns Hopkins University

A critical consideration in effective and measured public health responses to an outbreak of inhalational anthrax is the optimum duration of antibiotic prophylaxis. We develop a competing-risks model to address the duration of antibiotic prophylaxis and the incubation period that accounts for the risks of spore germination and spore clearance. The model predicts the incubation period distribution, which is confirmed by empirical data. The optimum duration of antibiotic prophylaxis depends critically on the dose of inhaled spores. At high doses, we show that exposed persons would need to remain on antibiotic prophylaxis for at least 4 months, and considerable morbidity would likely occur before antibiotic prophylaxis could even be initiated. At very low doses, 60 days of antibiotic prophylaxis is adequate. Exposure doses can be estimated from the cumulative attack rate up to the point antibiotic prophylaxis begins. The model explains that whereas < or =60 days of antibiotics were enough to protect persons in the 2001 U.S. outbreak, because doses were very low, at moderate or high doses considerably longer durations would be necessary to adequately protect exposed populations.

Publication Date
December, 2003
Citation Information
Ron Brookmeyer, Elizabeth Johnson and Robert Bollinger. "Modeling the Optimum Duration of Antibiotic Prophylaxis in an Anthrax Outbreak" Proceedings of the National Academy of Sciences Vol. 100 (2003)
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