中国严格的social distancing措施使新冠肺炎“传染率”（reproductive rate）从1人传染3.8人下降到0.32人。其原理在于，social distancing可防止感染者与健康人群密切接触，从而切断潜在的传染链（involves breaking potential chains of transmission by preventing infected people from coming in close contact with healthy ones）。