The effectiveness of social distancing in containing Covid-19

A statistical measure of the containment of Covid-19 is proposed to describe seven possible outcomes ranging from the worst outcome of 'beyond control' and the best outcome of 'under control with rapid progress towards zero infections'. This measure is used to examine the performance of 10 countries with emphasis on the role of government-imposed measures of social distancing (lockdown, etc.). The results show that social distancing is effective, even though it is difficult to separate the effect of government measures from that of social distancing triggered by personal initiatives. The experience of Sweden shows that social distancing as a personal initiative is inadequate for the purpose of containing the virus. The experience of Brazil shows that taking the virus lightly brings about serious consequences.