“The suppression-and-lift strategy is the most talked about amongst my ilk and in governments all over the world,” said Leung, who is also the dean of medicine at the University of Hong Kong. “You would need to keep on these control measures to varying degrees until one of two things happen: One, is there is natural immunity by active infection and recovery, or there is sufficiently wide availability of an effective vaccine administered to at least half the population, to create the same effective herd immunity. These are the only two ways of going about it.” Leung added that we’ll go through “several cycles” of tightenings and easings “before we will have resolution.”

Leung’s view is echoed in the scientific community. Research published by the COVID-19 Response Team at Imperial College London this month found that “intermittent social distancing—triggered by trends in disease surveillance—may allow interventions to be relaxed temporarily in relative short time windows, but measures will need to be reintroduced if or when case numbers rebound.” Writing for The Atlantic about how to cope with the virus in the United States, Aaron E. Carroll, a pediatrics professor, and Ashish Jha, a global-health professor, suggested a similar approach. “We can keep schools and businesses open as much as possible, closing them quickly when suppression fails, then opening them back up again once the infected are identified and isolated,” they wrote. “Instead of playing defense, we could play more offense.”