Population-based monitoring of COVID-19 infections has dramatically been absent in most populations on the planet. However, the Real-time Assessment of Community Transmission (REACT) was one of the rare exceptions. With Prof Paul Elliott, principal investigator of REACT at Imperial College, London and Prof. Natalie E Dean at Emory University, Atlanta, we review how REACT was done, what it did, and in how much it could serve as an example for the US. Moderators are: Alfredo Morabia at AJPH and Prof Vickie Mays at UCLA.
