Trajectory of the cumulative number of COVID-19 cases in a (a) linear scale and a (b) log scale. The increase in cumulative COVID-19 cases slowed between January 2020 and late February 2020. However, in early March 2020, the case trajectory in these five countries increased significantly 1(a). The increases were most stark from mid-March to 28 March 2020. The trend on the log-scale 1(b) indicates an exponential growth in cumulative cases for three countries—Thailand, Malaysia and Singapore—which was steeper between mid-January and mid-February and then reduced until early March. Overall, the log-scale 1(b) shows two trajectories: a lower trajectory (Brunei and Singapore) and a higher trajectory (Thailand, Malaysia and Indonesia) (3)