The Conversation: A new community case of Covid-19 in New Zealand is a matter of when, not if. Is the country prepared for it?

New Zealand has now gone for 100 days with no community transmission of Covid-19. One way to measure the effectiveness of public health measures such as contact tracing is the virus reproduction number: the number of secondary infections for each new positive case. If this number can be kept below one, then one missed case at the border won't lead to an outbreak.