Epidemiologist Michael Baker says Auckland shifting to COVID-19 alert level 2 is reasonable, as we're not seeing widespread unexpected community spread.
The Otago University professor says the main source of incursion still appears to be from a failure at the border.
"I think it's still looking very much like a border failure - a leakage of cases somehow from the airside of Auckland Airport," he told Newshub.
LSG Sky Chefs is close to the airport and where the first positive case in this outbreak worked. The worker was one of three people from the same family who tested positive for the UK variant.
The mother, a laundry worker at LSG, may have got the virus through contact with another higher-risk border worker, like someone at the airport.
It was the laundry worker's daughter, a Papatoetoe High School student, who was first to report symptoms.
There are three more community cases: another two students at the school, and another member of their family.
But Prof Baker says the new cases appear to have caught it from the original Papatoetoe High School student.
"If there had been any hint that they had been upstream cases - so they were the source of the outbreak - then I think it would be a very different situation at the moment," he explained.
"I think on balance this is a reasonable decision - but like everything, it's a calculated risk."
What's also a risk is that it's highly likely we'll have more cases of the UK variant confirmed.
Canterbury University Professor Michael Plank, from the School of Mathematics and Statistics, provided Newshub with data to give an indicative example of how the new UK variant would spread compared to the original strain of the virus. The projections were based on spread without any alert levels or masks being used.
After 10 days, the UK variant starts to open a gap; at 15 days, there's quite a large difference; and by 30 days, the difference has grown to more than 2500 cases.
Des Gorman, Professor of Medicine at Auckland University, says if there are vectors out there that we don't know about, they're "far more likely to infect other people than the original variant".
Prof Baker says the current alert levels need review. He suggests making masks mandatory indoors, even at level 2.
"It needs more layers so it's more nuanced, because we need to send a signal to Aucklanders that it's not business as usual."
He says now, more than ever, we need to be alert to any symptoms of the virus.
