Listening to Bluetooth Beacons for Epidemic Risk Mitigation

During the ongoing COVID-19 pandemic, there have been burgeoning efforts to develop and deploy digital contact tracing systems to expedite contact tracing and risk notification. Unfortunately, the success of these systems has been limited, partly owing to poor interoperability with manual contact tracing, low adoption rates, and a societally sensitive trade-off between utility and privacy. In this work, we introduce a new privacy-preserving and inclusive system for epidemic risk assessment and notification that aims to address the above limitations. Rather than capturing pairwise encounters between user devices as done by existing systems, our system captures encounters between user devices and beacons placed in strategic locations where infection clusters may originate. Epidemiological simulations using an agent-based model demonstrate several beneficial properties of our system. By achieving bidirectional interoperability with manual contact tracing, our system may help reduce the effective reproduction number already at adoption levels of 10%. The use of location and environmental information provided by beacons allows our system to achieve significantly higher sensitivity and specificity than existing systems and thus may improve the efficacy of contact tracing under limited isolation and testing resources. Moreover, to achieve high utility, it is sufficient to deploy beacons in a small fraction of strategic locations. Finally, our simulations also show that existing systems could inherit these beneficial properties if they integrated the beacons used by our system.