Fig. 1.

Epidemic curve indicating the date of onset of COVID-19 cases among passengers on the flight, January to February 2020. (A): The case passengers flew from China to Singapore on 19 January (One passenger departed from Hangzhou; and the remaining 15 case passengers departed from Wuhan.). (B): The flight departed from Singapore to Hangzhou on 24 January and the passengers were placed in medical isolation and under observation on arrival in Hangzhou. (C): All passengers had samples collected for testing on 26 January. (D): All passengers had a second set of samples collected on 6 February. (E): The passengers from places other than Wuhan ended their medical isolation on 8 February. (F): Those who departed from Wuhan ended their medical isolation one week later on 15 February.