Assessing public health threats: An overview of coordinated threat assessment at the Public Health Agency of Canada.

Background: The early detection, assessment, and communication of potential public health threats are key activities in mitigating public health impacts by ensuring the timely deployment of an appropriate response. The Public Health Agency of Canada (PHAC) uses a standardized methodology to consolidate scientific and technical subject matter expertise on a weekly basis to systematically characterize and assess emerging public health signals and communicate assessments to decision-makers. Methods: Public Health Agency of Canada's coordinated threat assessment process, and the standardized methodology used to characterize and assess threats, are described. Results: The coordinated threat assessment methodology uses a standardized method that includes engagement with subject matter experts across PHAC to assess, document, and communicate the characterization of each threat. Three key attributes are used to assess each threat based on the concern for human health, the potential to affect Canada, and the concern that Canada has insufficient control measures to manage a specific threat. Qualitative criteria for each threat attribute are used to assess a threat based on 'high', 'moderate', or 'low' levels. An overall assessment is based on the three threat attributes and is accompanied by a narrative rationale to support the assigned threat level. Conclusion: The standardized threat assessment methodology provides a coordinated and systematic process to characterize and assess public health threats in a consistent and timely manner. The framework reflects important elements to consider in terms of public health significance, allows for flexibility in the indicators used to characterize a public health threat, and is applicable to any threat of public health concern.