There has been significant interest in leveraging smartphone apps for contact tracing, a public health strategy that involves tracking people who are COVID-19 positive to identify disease hot spots. Traditionally this is done by workers on foot and over the telephone, and we know this labor-intensive method works — it has helped in the elimination of smallpox and in curbing the spread of sexually transmitted infections. However, the efficacy of the app-boosted method is still unknown.
Unfortunately, pressure to ease lockdowns has led to a mad dash to develop and use such apps for COVID-19, resulting in a wildly different array of options. As public health departments are pushed to follow suit, we must be careful about which technologies we adopt.
Several dozen states and companies have already started developing and using digital tools. In the spring, Utah released an app, called Healthy Together, which was built by a social