Different strategies are employed worldwide to face the reality of hospital and intensive care unit (ICU) restricted capacity. China, for instance, did not wait long to implement restrictive measures, like city lockdowns and school closures. On the other hand, England first believed that being too restrictive too early would lead to a large second epidemic once measures were lifted. They finally applied restrictive measures after a sudden rise of infected cases.
Behind these different defensible measures lie mathematical computer simulation models applied to the epidemiology of infectious disease. These mathematical models were used to model the Ebola and Zika viruses in the past.
There is still debate among scientists about which mathematical model most accurately represents characteristics of SARS-CoV-2 and the affected population, and about the scope of such models within government authority restriction plans.
Martin Enserink, Kai Kupferschmidt, Mathematics of life and death: How disease models shape national shutdowns and other pandemic policies, Science magazine, March 25, 2020