Come out of lockdown too early and we'll face the prospect of having Christmas basically cancelled, a leading expert has warned.
Prime Minister Jacinda Ardern on Friday said Auckland and Northland would likely spend a couple more weeks at alert level 4, the strictest lockdown in the Government's arsenal, while everywhere else is all set to move to level 3 from Wednesday.
While the lengthening of restrictions in Auckland was widely expected, many South Islanders have expressed disappointment they can't move to level 3 sooner, or even perhaps level 2.
"I guess the message the Prime Minister made... was that the bar's been sent a lot higher because of the highly contagious nature of the Delta variant," Christchurch Mayor Lianne Dalziel told Newshub.
Business leaders and other Mayors reacted with anger, saying there aren't any known cases in the entire South Island and questioning why they're only going to level 3, which still has tight controls on movement and business operations.
University of Auckland microbiologist Siouxsie Wiles says with the current outbreak involving the highly contagious Delta variant, there is no such thing as "being too cautious".
"We have to be really clear that we haven't got any transmission chains that we don't know about or cases that could be incubating before we go down the alert levels."
Delta is about twice as infectious as earlier strains of the virus, and the South Island has a few hundred close contacts of people confirmed to be infected. Wednesday, when the level is set to change, will be two weeks from when level 4 restrictions came on - anyone who was infected before level 4 started would likely have started showing symptoms by then.
If someone is infected and they're contagious, case numbers could rise quickly - even under level 4. A recent study found household members in the same bubble were 66 percent more likely to contract COVID-19 themselves if exposed to Delta than if it was Alpha, the highly infectious variant which emerged in the UK late last year.
"From the data we've seen overseas, once somebody in a house is highly infectious, then you tend to see everybody else in the house also also tests positive," said Dr Wiles. "We'll certainly see that - we'll see our case numbers continue to rise as people from infected households become positive themselves."
At Christmas, Kiwis like to get together with the wider whanau - something we got to enjoy last year while many of our English friends and family were stuck at home during a winter surge, driven by Alpha.
"The last thing we want is to move down the alert levels too quickly so that in a few weeks' time we end up with cases we didn't know about... and basically Delta comes back and we end up having to go back to alert level 4," said Dr Wiles.
"The timing of this means if that happens, we'd probably be in restrictions at Christmas time. Everybody wants us to get back to alert level 1 as soon as possible, but that means doing it slowly."
Going to level 3 while there's known transmission poses a huge risk, she said, even if most of us are still working at home where possible,
"At level 3 we have quite a few businesses that operate, and though those businesses don't have interactions with customers, they do have people working in them. Those people will all be leaving their bubbles and working together - that basically connects more households together.
"So if somebody in a business ends up testing positive, we can expect to see it move both through that business, through that workplace, and then out into everybody's families who's connected to that workplace."
So far there have been 347 confirmed cases in the current outbreak. With that number, Dr Wiles said it's time to start mentally preparing for the possibility our death toll to date - just 26 - will rise.
"We're starting to see people being hospitalised. We know it takes anywhere from two to six weeks to start to see people ending up in hospital and then potentially dying. With the size of this outbreak, we can expect something like that to happen... it's really in our best interest to stamp it out. We do not want this outbreak to get any bigger."
Nineteen people were in hospital at the time of Friday's update from Ardern and Director-General of Health Ashley Bloomfield.