Public health vaccination policies for containing an anthrax outbreak

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Concern about biological weapons has raised questions about the most effective public health policies to contain an anthrax outbreak1,2,3. We developed a probability model to predict the impact of different anthrax antibiotic and vaccination policies. An anthrax outbreak can be significantly contained by minimizing the delay until initiation of antibiotic prophylaxis. However, even if mass distribution of antibiotics is completed within six days of the initial exposure, then at most about 70% of cases can be prevented. Post-exposure vaccination will not significantly increase that prevention rate if adherence to antibiotic regimens is similar or higher than that attained in the 2001 US outbreak4. However, post-exposure vaccination can be useful either in shortening the duration of a prolonged antibiotic regimen, in the event of an antibiotic-resistant strain, or if antibiotic adherence rates are very low. Here we show that a mass pre-exposure vaccination programme for the general population would require very high population coverage rates to significantly increase prevention rates from that achieved with targeted and rapid post-exposure prophylaxis programmes.

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Figure 1: Percentage of cases prevented versus delay of initiating mass distribution of antibiotics.
Figure 2: Days that antibiotic therapy can be shortened by post-exposure vaccination versus vaccine efficacy.


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The authors acknowledge the comments of the Anthrax Modeling Working Group of the Secretary's Council on Public Health Preparedness of the Department of Health and Human Services. This research was partially funded by the Fogarty International Center and a grant from the National Institute of Allergy and Infectious Diseases.

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Correspondence to Ron Brookmeyer.

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The authors declare that they have no competing financial interests.

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Brookmeyer, R., Johnson, E. & Bollinger, R. Public health vaccination policies for containing an anthrax outbreak. Nature 432, 901–904 (2004) doi:10.1038/nature03087

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