People Count: Contact-Tracing Apps and Public Health

An introduction to the technology of contact tracing and its usefulness for public health, considering questions of efficacy, equity, and privacy.

How do you stop a pandemic before a vaccine arrives? Contact tracing is key, the first step in a process that has proven effective: trace, test, and isolate. Smartphones can collect some of the information required by contact tracers—not just where you've been but also who's been near you. Can we repurpose the tracking technology that we carry wit...