A century of assessment: A systematic review of biothreat risk assessments.

Throughout the past century, assessments of the risks and benefits posed by high-consequence biological agents have guided US decision-making on weapons research, countermeasure development, and security policy. However, the dispersed nature of these biothreat risk assessments has presented various difficulties, such as duplicative effort, inconsistent approaches, and sectoral echo chambers. In this paper, we set out to evaluate the world's largest repository of biothreat risk assessments to better understand the historical risk assessment landscape, contextualize current risk assessment output, and extract major themes that may shape future risk assessment development and evaluation. To these ends, we developed a decade-by-decade systematic review of the motivations, context, and conclusions of collected biothreat risk assessments. Our results identify particularly important themes and ideas that have shaped modern biosecurity policy, exhibiting the waxing and waning of approaches and perceptions throughout time. Analysis of these biothreat risk assessments identifies key trends, contextualizes modern risk assessment practices, and gives insight into the trajectory of the field moving forward. Collectively, the lessons learned give perspective on the relative success of approaches and modes of thinking in biothreat risk assessment, providing essential insights for risk assessors of the future.