The coronavirus pandemic is closing businesses across the United States, including this restaurant in Boston. By Warren CornwallScience’s COVID-19 reporting is supported by the Pulitzer Center.Economist Sergio Rebelo has spent the past 2 weeks holed up in his Chicago home, working feverishly to crack the economics of the coronavirus.Armed with a hybrid model that combines how viruses spread with how people work and consume, the Northwestern University researcher is one of a number of macroeconomists now trying to shed light on the balance between the economic impact of locking down major parts of the economy and the economic damage wrought by the disease itself. “When you think about the optimal policy, you really want to see the effect