New Zealand is on alert as COVID-19 returns. This is what we need to stamp it out again
- Written by Michael Plank, Professor in Mathematics, University of Canterbury

Auckland, and possibly other parts of New Zealand, almost certainly have more cases of COVID-19 in the community than the four new cases confirmed yesterday.
Prime Minister Jacinda Ardern activated a resurgence plan late yesterday, placing all of Auckland back under alert level 3 restrictions from today until midnight on...