title: Modeling the optimum duration of antibiotic prophylaxis in an anthrax outbreak.
abstract: 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.
authors.affiliation: Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA. rbrook@jhsph.edu
authors.forename: Ron
authors.initials: R
authors.lastname: Brookmeyer
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Johnson
authors.forename: Robert
authors.initials: R
authors.lastname: Bollinger
mesh_terms: D000881:Anthrax / Q000453:epidemiology* / Q000517:prevention & control*; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D001408:Bacillus anthracis / Q000187:drug effects / Q000472:pathogenicity / Q000502:physiology; D023482:Bioterrorism; D015169:Colony Count, Microbial; D004196:Disease Outbreaks / Q000517:prevention & control; D004334:Drug Administration Schedule; D006801:Humans; D008954:Models, Biological; D015233:Models, Statistical; D011634:Public Health; D012306:Risk; D013171:Spores, Bacterial / Q000187:drug effects / Q000472:pathogenicity / Q000502:physiology; D014481:United States / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents