Fig. 2.

Estimated epidemic curves of COVID-19 under different intervention scenarios across 135 countries or territories in 2020. (a) Implementing travel and physical distancing interventions during various periods (the median and interquartile ranges of estimates are shown); (b) 8-week interventions with various levels of travel and contact rates (in panels (a) and (b), the travel and contact levels after relaxing interventions were assumed to be 70% of normal level before the outbreaks, if the travel and contact rates in a country or territory were lower than 70%); (c) scenarios of various travel and contact rates after lifting 8-week interventions; (d) the estimated epidemic curves under interventions up until December 31, 2020 based on travel and contact levels by May 2, 2020: 14 countries/territories with travel and contact rates higher than or equal to 70%, and 121 countries/territories with the rate less than 70% at any week; (e) estimated epidemic curves under interventions implemented earlier than actual timing, under the scenario of interventions implemented by December 31, 2020; (f) estimated epidemic curves under interventions implemented later than actual timing, under the scenario of interventions implemented up until December 31, 2020. The orange and red vertical dashed lines indicate the dates the WHO declared COVID-19 a Public Health Emergency of International Concern and a pandemic, respectively. The pink vertical lines indicate the dates that lockdown/physical distancing measures were implemented by each country or territory.