The head of the U.S. Centers for Disease Control and Prevention, Robert Redfield, says contact tracing will be vital in the next phase of the coronavirus pandemic in the United States.
Poor countries have advice to offer.
Contact tracing is used all over the world, including in the U.S. The idea is to track down anyone in recent contact with a newly diagnosed patient, then monitor the health of these contacts. In the developing world, it's been a valuable tool in fighting infectious diseases like Ebola and tuberculosis. Public health workers there have lots of experience.