Despite the country shortly set to ease lockdown restrictions and drop down to alert level 3, Dr Ashley Bloomfield is warning we must remain vigilant against a second wave of COVID-19.
Speaking on The AM Show on Tuesday, the Director-General of Health clarified that even though the Government was working to eliminate the virus from our shores there will be cases that remained here.
"Eliminate is not eradicate," Dr Bloomfield said. "Eradicate is what the world has managed to do around smallpox. Eliminate is actually get it down to a very low level, and a level that we've got confidence we know where any cases that come up are and that we can stamp them out really quickly. So it's not the same as completely eradicating it."
On Monday, Prime Minister Jacinda Ardern announced that alert level 4 - imposed at the end of March - would be extended until next week. The original four-week period was set to end late on Wednesday night, but now Kiwis will have to wait until 11:59pm on Monday for restrictions to be eased.
The alert level will then be lowered to 3 for a further two weeks before being assessed once again.
Dr Bloomfield says extending the lockdown until early next week was one of three options presented to Cabinet - the other two were to change the alert level on Wednesday as initially planned or to extend the lockdown further.
"Our view was, look, we are close - we're certainly not out of the woods and we won't be even when we move to level 3, we've got to keep very vigilant," Dr Bloomfield told The AM Show. "But our view was that those extra few days were important to just get us in that position where we could be really confident that the time spent in alert level 4 had been absolutely maximised. And my sense is there's quite wide support for that."
Although the aim is to eventually record no new cases, it is expected that that will still not happen for a while yet.
"I'm hoping we will get to zero cases, but the key thing is there may well be some transmission happening within, for example, families of cases that we know where people have been infected a few days ago. But what we are doing is very wide testing around any new case so the key point here is whether it's zero or a small number - and I would say anything under 10 is a nice, small number - it's knowing exactly where those infections are coming from.
"That's the thing that gives us a high level of confidence we've got it under control."
Decision informed by better modelling
Although Dr Bloomfield admitted that many experts had differing views over the best course of action, and different modelling showed a range of possible scenarios, he said data was becoming increasingly more reliable.
"I think what the difference has been over the last four weeks is, prior to going into lockdown the modelling was just using data from overseas and projecting that on to New Zealand. What we've been able to over the past few weeks, of course, is be able to populate those models with actual data from New Zealand to provide a more realistic forecast of what might happen," Dr Bloomfield said.
Initial modelling showed that if no lockdown was put in place as many as 14,000 Kiwis could die from COVID-19.
"Schools not a high-risk setting"
According to the new rules, schools and early childhood education centres will be able to open from April 29, though parents who are able to keep their children at home can still do so.
The issue of whether to allow schools to open has caused controversy over the past few weeks, with many questioning if appropriate social distancing can be put in place.
But Dr Bloomfield says the decision to allow schools to open was based on firm data.
"If you look around the world - and we had a really good look at all the evidence - actually schools are not a high-risk setting for students getting infected," he told The AM Show.
"What we've found of course is that children and teens are less likely to get infected, and if they are they are less likely to be affected by this virus."
He also said it was "very unusual" for children to pass the virus on to adults.
"We're really confident that the measures that the education sector are going to put in place inside early childhood education centres and in schools will actually keep students safe, keep staff safe and of course keep families safe - that's the whole point."
Could we go back to level 4?
Although the country was well underway to stamping out the virus, Dr Bloomfield warned that it was still possible to shift back to alert level 4, even after restrictions are eased.
"Whether or not we have to go back to level 4 is completely dependent on New Zealanders," Dr Bloomfield said.
"And they've shown in alert level 4 that they get it, that they know what they need to do to break the chain - which we've done - so we can do our bit but, as the Prime Minister said yesterday, even in alert level 3 if anything we need to be even more vigilant.
"We don't have the protections of a full lockdown so once again it's actually up to all of us to do our bit. That will be what will stop us having to go back into level 4, ultimately."