The presence of previously infected people in the community, Streeck and colleagues believe, will reduce the speed at which the virus can move in the area. They also outline a process by which social distancing can be slowly unwound, especially given hygienic measures, like handwashing, and isolating and tracking the sick. They think if people avoid getting big doses of the virus—which can happen in hospitals or via close contact with someone infected—fewer people will become severely ill, “while at the same time developing immunity” that can help finally end the outbreak.