Medical mitigation model: quantifying the benefits of the public health response to a chemical terrorism attack.

The Chemical Terrorism Risk Assessment (CTRA) and Chemical Infrastructure Risk Assessment (CIRA) are programs that estimate the risk of chemical terrorism attacks to help inform and improve the US defense posture against such events. One aspect of these programs is the development and advancement of a Medical Mitigation Model-a mathematical model that simulates the medical response to a chemical terrorism attack and estimates the resulting number of saved or benefited victims. At the foundation of the CTRA/CIRA Medical Mitigation Model is the concept of stock-and-flow modeling; "stocks" are states that individuals progress through during the event, while "flows" permit and govern movement from one stock to another. Using this approach, the model is able to simulate and track individual victims as they progress from exposure to an end state. Some of the considerations in the model include chemical used, type of attack, route and severity of exposure, response-related delays, detailed treatment regimens with efficacy defined as a function of time, medical system capacity, the influx of worried well individuals, and medical countermeasure availability. As will be demonstrated, the output of the CTRA/CIRA Medical Mitigation Model makes it possible to assess the effectiveness of the existing public health response system and develop and examine potential improvement strategies. Such a modeling and analysis capability can be used to inform first-responder actions/training, guide policy decisions, justify resource allocation, and direct knowledge-gap studies.