The health expert whose modelling was released by Prime Minister Jacinda Ardern to show hospitals coping with the outbreak says he would wait longer before easing restrictions in Auckland.
Counties-Manukau director of population health Dr Gary Jackson said it's unclear how much case numbers will increase by after Auckland moves into step 2 of alert level 3.
The outbreak is currently tracking according his model's median projection, which has daily case numbers peaking at 200 a day later this month, including 11 ICU admissions a week.
The upper projection would see daily case numbers peaking at 314 a day by early December, including 16 ICU admissions a week.
Ardern and director-general of health Ashley Bloomfield presented the modelling on Monday, when Ardern revealed Cabinet's in-principle decision to move Auckland into step 2 of alert level 3 from next Wednesday.
But the model assumes the current level 3 restrictions in Auckland, and moving to step 2 will allow more ways for the virus to spread.
"I worry that it's too risky," Jackson told the Herald.
"I'd much rather we had the higher vaccination rate first and then we did the easing. But I also get the impatience of everybody [saying], 'look, I'm vaccinated, why can't I go and do my business?'"
Ardern and Bloomfield both said that the increase in cases won't be too large, and Jackson said he hoped opening up retail shops and public facilities won't make a "huge" difference.
"But with every little difference, of course, it just gives a bit more interaction, a bit more of a chance for the virus to jump around the place."
A sophisticated Te Pūnaha Matatini model looking at neighbourhoods across the country shows that the number of individuals who are interconnected can jump by a factor of 15 following a shift from alert level 4 to 3.
There are still hundreds of thousands of unvaccinated people in Auckland - including 300,000 children who are ineligible - who will be able to head to shops, libraries and museums.
There are no number limits on these places at step 2 of level 3, except to accommodate physical distancing requirements.
The Red setting of the traffic light system was safer than that, Jackson said, because the ability for unvaccinated people to meet in large groups was severely curtailed.
"Unvaccinated people will still be like at level 3. They can't go into hospitality or shops, but vaccinated people can. That will be more restrictive on the virus than step 2 of level 3.
"It is a shame that the vaccination certificate wasn't available a little bit sooner, because that would have made it much easier to start doing some of these changes more safely."
Young Māori on the Delta frontline
Jackson said he would have waited another week and moved Auckland to step 2 in the middle of the month.
"That way there's only about two weeks until the [traffic light system] comes in, so you haven't got time to do too much damage."
There will still be pockets of unvaccinated communities, even if the 90 per cent target in each DHB is met.
"It leaves a large pool of people who the virus will spread through, and the virus will find them," Jackson said.
"If anybody's unvaccinated, the virus will find them over the next year."
Those who are most on the Delta frontline are young Māori, who are the least vaccinated group, and make up a higher proportion of the population in communities where the virus has been circulating.
The High Court on Monday released a decision in favour of the Whānau Ora Commissioning Agency, which had wanted information from the Ministry of Health so health providers could door-knock the unvaccinated.
Jackson said Counties-Manukau also wanted Māori health providers to be able to do this.
"But we weren't permitted to have the vaccine status of people in their houses for privacy reasons.
"It's frustrating, but I can see both sides. You start to walk into people's medical privacy."
ICU capacity not at the edge of a precipice
Jackson said ICU staff across Auckland would be able to cope with the upper projection of 314 cases a day and 16 new ICU patients every week.
"Middlemore's got nobody in ICU with Covid for the first time since August. Nobody's got seriously ill with Covid in the last couple of weeks.
"Some will come back in again, but at the moment, we're in quite a good space."
The lower hospitalisations were in part because of the younger demographic who are affected by the outbreak. The younger the person, the less likely they'll need hospital or ICU care, all other things being equal.
"And we've had virtually nobody over 65. That's the part of the population that's really well vaccinated, and they're also much better at following the level 3 rules."
Jackson added that the number of new ICU patients last week was fewer than the median projection, but hospitals are still preparing for an influx of cases, including for 30 ICU beds constantly occupied by Covid patients.
It was hard to gauge the point at which hospitals won't be able to cope, he said.
"At the moment, we're coping quite well because we've got a whole workforce who would normally be doing elective surgery who are available to fill rosters and do other things.
"But clearly, we're going to have to work out a way of getting those operations and procedures going again. The longer you delay, the more harm you've been doing to people who need those operations."
Covid was also seasonal, so pressure on hospitals would ease even more as the summer season kicked in, he said.
"I'm feeling quite good that we will be an elective surgery going again, in January, like we would in a normal year."
Jackson said it would be a different story if there were 1000 cases a day, which would see 50 new ICU patients a week.
"That would be what happened in Sydney and Melbourne, including a number of deaths a day. That's what we have avoided.
"It could still potentially happen if we did a Freedom Day, but I can't see our Government letting that happen."
Jackson's previous modelling - for what will happen next year - showed weekly cases in the Auckland and Northland regions stabilising at 590 cases a week and 160 deaths a year, though this could hit 5400 cases a week and 1000 deaths a year if no public health measures or Covid restrictions were in place.
Ardern has talked about using surge vaccinations and localised lockdowns next year if the virus crept into pockets of unvaccinated communities.
Jackson said that people should realise that moving to the traffic light system won't mean an end to Covid restrictions.
"There are still going to be cases, they're still going to have to isolate, and there's a whole pile of things that you need to do as a health system to suppress the spread of the virus so it doesn't just go and find 100,000 people all at once.