The term points to the need for a monumental effort to ramp up testing speed and capacity, as well as an extensive — if not ubiquitous — tracing program. Epidemiologists believe that if it is properly employed, testing and tracing can allow the U.S. to open some businesses and relax social distancing requirements. But it will almost certainly need to be a slow and methodical process or else the country risks undoing the good from the initial wave of lockdowns.