Physical Approaches to Civilian Biodefense: Identifying Potential Preparedness Measures for Challenging Biological Threats

As biotechnology continues to advance—driven by progress and democratization in such fields as synthetic biology and artificial intelligence—so does its potential to improve lives. At the same time, these developments bring new challenges, including the need to responsibly manage risks associated with the release of high-consequence pathogens. To ensure national preparedness for all biological threat scenarios, no matter how severe, the United States must develop practical strategies to sustain critical functions at scale.

Our aim in this study is to probe the plausibility of protecting the United States against the following three major biological threat scenarios that challenge the United States' existing defenses:¹

• a fast scenario, challenging countermeasures with a rapidly spreading outbreak of a lethal human-to-human-transmissible pathogen
• a silent scenario, challenging detection with a pathogen that infects much of the population before infected people display visible symptoms
• a saturating scenario, challenging countermeasures involving a pathogen that replicates and persists in the environment.

For each of these categories, we present a near-worst-case paradigmatic scenario but assume a near-best-case societal response with bureaucratic swiftness and wide public compliance, allowing us to assess the adequacy of existing and possible defenses independent of human and organizational behavior.

For each scenario, we set notional values for the key parameters that drive the scenario's severity. Given those parameter values, we assess numerical requirements for physical defenses that would provide capabilities relevant to protecting the U.S. population under each of these scenarios until effective pharmaceutical countermeasures could be developed and deployed. Then, we introduce one possible way that the United States could meet those requirements. Finally, we identify actions the U.S. government could take to implement that preparation in the short, medium, and long terms. Although this analysis uses the vantage point of the United States, the requirements and recommendations described here are designed to be adaptable to other countries to support their efforts to achieve resilience against catastrophic biological threats. To keep our analysis manageable, we focus on the plausibility of what we term physical defenses: material, nonpharmaceutical defenses within the bounds of humanity's current conceptual knowledge.

The results of our analysis for each scenario are summarized in Table 1. Much future work is needed to refine our analysis here and potentially expand it to other scenarios, but our results suggest that physical defenses against these scenarios are indeed plausible. Targeted investments within the reach of single governments and possibly philanthropic actors can contribute to making the United States and other countries resilient to some of the most significant risks that the world may face.