A risk analysis approach to selecting respiratory protection against airborne pathogens used for bioterrorism

The authors present a quantitative risk analysis approach to estimating infection risk due to airborne pathogens exhibiting relatively large infectious dose values. The method is applied to hypothetical scenarios involving airborne spores of Bacillus anthracis. The method combines the estimated parameters for exposure intensity, the pathogen dose-response relationship, and respirator penetration values (if respiratory protection is used). Because knowledge of the true parameter values will be uncertain, an uncertainty analysis is an essential part of the process. Given a specified value for acceptable infection risk, the method permits choosing a respirator that sufficiently reduces exposure to meet the acceptable risk criterion. A strength of the risk analysis approach is its transparency, in that the model structure and data inputs are explicitly identified. Further, risk analysis informs the expert judgment that must typically be applied in selecting respiratory protection against airborne pathogens.