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Society For Risk Analysis Annual Meeting 2008

Risk Analysis: the Science and the Art

Session Schedule & Abstracts

* Disclaimer: All presentations represent the views of the authors, and not the organizations that support their research. Please apply the standard disclaimer that any opinions, findings, and conclusions or recommendations in abstracts, posters, and presentations at the meeting are those of the authors and do not necessarily reflect the views of any other organization or agency. Meeting attendees and authors should be aware that this disclaimer is intended to apply to all abstracts contained in this document. Authors who wish to emphasize this disclaimer should do so in their presentation or poster. In an effort to make the abstracts as concise as possible and easy for meeting participants to read, the abstracts have been formatted such that they exclude references to papers, affiliations, and/or funding sources. Authors who wish to provide attendees with this information should do so in their presentation or poster.

Common abbreviations

W2-E Anthrax Attacks Room: Commonwealth B   10:30 AM-Noon

Chair(s): Greg Paoli

W2-E.1  10:30  Economic Impacts of the Amerithrax Attacks. Schmitt K*; Concordia University   ketraschmitt@gmail.com Abstract: The potential economic impacts of bioterrorism are widely predicted to be significant, however, little research exists to evaluate the impact of bioterrorism events. Moreover, no economic impact assessment exists for the most serious bioterrorism event in the United States to date, the letter attacks of 2001 involving anthrax contamination, widely referred to as the amerithrax attacks. This study attempts to quantify the economic impact of the amerithrax events. These impacts are evaluated by determining the costs directly associated with the event as well as the specific industries impacted. These direct costs include the costs of decontamination and medical services associated with the letter attacks, as well as an evaluation of the broader costs of detection devices and market impacts of the events on the postal service and US government. In particular, understanding impacts of the amerithrax attacks on consumption behavior is key to estimating economic impacts. An input-output analysis is conducted to evaluate the inter-industry effects associated with the amerithrax events. An important methodological consideration in this analysis is the careful accounting of payment sources for remediation and detection. In this way, transfer payments among taxpayers, the government and affected industries are explicitly stated so that economic winners and losers associated with the events can be clearly identified. This avoids a common pitfall in economic evaluations of disasters, in which injections to the economy are disregarded or counted as economic damage.

W2-E.2  10:50  Surface Sampling Areas Required to Inform Risk-based Responses to B. anthracis Contamination . Hong T*, Gurian PL; Drexel University   hongtao510@gmail.com Abstract: In many cases human health risk from biological agents is associated with aerosol exposures. Concentrations found on surfaces may be used to infer future or past aerosol exposures. When concentrations exceed decision threshold values, they would trigger response actions, such as remediation (to avoid future risks) or prophylactic antibiotics (to mitigate risks of past exposure). In this project, analytical equations are developed to relate the risk from aerosol exposure to the concentrations of spores on surfaces. This allows for the determination of decision threshold concentrations for surface samples, if the overall level of acceptable risk is specified. However, biological agents present risks at extremely low concentrations, which means that a non-detect result may not guarantee that the agent is present at a concentration below the decision threshold value. To address this concern, estimates of sampling areas required to demonstrate compliance with surface concentration standards are developed. It is assumed that microbial occurrence follows a Poisson distribution. This allows the principles of classical statistical inference to be used to estimate surface sampling areas that would allow for classification of a site as below the decision threshold at specified levels of confidence given non-detectable results. This method is then extended to consider non-zero method detection limits. The calculated sampling areas are large but may not be totally infeasible.

W2-E.3  11:10  An evaluationof the risk threshold for prophylaxis and treatment after an anthrax release. Mitchell-Blackwood J*, O'Donnell C, Gurian P; Drexel University   jade@drexel.edu Abstract: In the wake of the 2001 terrorist attacks, the use of Bacillus anthracis (anthrax) in bioterrorism is of concern. Thus, it is necessary to prepare a contingency plan in case of such an attack. While antibiotic prophylaxis alone or in combination with vaccination is clearly justified for individuals exposed to substantial quantities of spores, there are likely to be very large numbers of individuals exposed to very small quantities of spores. The risk of infection is variable based on the size of the release and/or the amount of exposure to which a person is subjected. At lower risk, the “no action” alternative is therefore important to investigate. This study addresses the establishment of a risk threshold at which individuals should receive antibiotics, be vaccinated or both. A decision model was developed to evaluate the costs and benefits associated with each alternative. The risk of infection necessary to justify treatment was estimated to 0.0052 percent or 1 in 20,000 individuals. This conclusion is sensitive to a variety of factors, including the monetary value of a quality adjusted life year.

W2-E.4  11:30  Consequence mitigation of hypothetical medical countermeasures for Anthrax exposure in a bioterrorism attack. Hale TL*, McMillan NJ, Dingus CA, Burns JM, Wheeler ED; Battelle Memorial Institute   halet@battelle.org Abstract: Recent Homeland Security Presidential Directives (HSPDs) 10 (Biodefense for the 21st Century) and 18 (Medical Countermeasures against Weapons of Mass Destruction) have provided specific requirements from the President for executing risk assessments specific to Weapons of Mass Destruction (WMD) for the purpose of guiding strategic planning in such areas as biodefense and medical countermeasure acquisition to defend against chemical, biological, radiological, and nuclear (CBRN) terrorism. In support of this activity, the Department of Homeland Security’s Science and Technology Directorate has undertaken detailed modeling of how the public health system would be able to mitigate fatality and illness consequences of such an attack, should it occur. In this talk, a simple discrete event simulation model describing the progression of events following a covert terrorist attack with a biological agent is briefly described. The progression of events after exposure of a group of people to a biological agent is highly dependent on the biological agent. Based on the 2001 Amerithax attacks, disease etiology is modeled to resemble anthrax. Critical parameters impacting the ability to treat disease include time between exposure and treatment, as well as countermeasure efficacy and quantity parameters. The model is then exercised under a variety of assumptions on the timeline between exposure and treatment and the prophylactic and treatment capabilities of several medical countermeasure strategies.

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