As the US faces record COVID-19 infections, effective use of exposure notification apps is unlikely given slow adoption and lack of data on their efficacy (Washington Post)

Washington Post:
As the US faces record COVID-19 infections, effective use of exposure notification apps is unlikely given slow adoption and lack of data on their efficacy  —  The United States is grappling with record-high infections, but adoption of the system is still far behind what its creators and proponents envisioned