the catch is, if we're really hiding, we must have got thousands of deaths by now. Just see how quickly it spread in Korea, Italy and Iran. Hiding (thus no action can be done) for 1.5 months is a sure way to suicide, given the amount of traffic in/out of Vietnam and the population density.

Or you can see that in the past week alone we got 27 cases, starting from 2 planes. And the number is low because we vigorously chased people down to test them all and quarantine them. Had we let them go loose those 2 cases alone could spread to hundreds.