The chances of other shoppers having caught Covid-19 from an infected man who made a rogue visit to an Auckland supermarket would likely be "very low", an expert says.
Countdown in Victoria St West was today closed and being cleaned after a newly-arrived 32-year-old with the virus last night snuck out of managed isolation and spent 20 minutes there.
While CCTV footage from within the supermarket has confirmed there was no close contact between the man and any staff or customers during his time there, the store was ordered shut today, with a security guard turning people away.
The man, who is now facing charges, had been wearing a mask, but not for the whole 70 minutes he was away from the Stamford Plaza and in Auckland's CBD.
For those who happened to be in the supermarket around the same time, the risk was probably small, said Otago University epidemiologist Professor Michael Baker said.
"I'd take it he was wearing a mask at that point, which would be pretty important because there is a lot of source protection, and the chances of infecting people around him would've been greatly reduced," Baker said.
"You do have to consider some basic factors: how much contact did he have with local people? How long was he indoors and outdoors? Was he wearing a mask? All of these are very relevant.
"But if he was wearing a mask, and the amount of contact with people as very short, the risk of him affecting people around him will have been very low."
Baker said such breaches should be kept in proportion, and used to improve processes, rather than as blaming exercises.
"This is something we are going to have to live with for a long time, so we've got to take a constructive approach, and not equate breaches with outbreaks, as they're two very different things."
Other scientists have also pointed out that Kiwis will have to accept an increased risk if New Zealand opts to open its borders to more people.
"With current travel numbers, we expect around 12 cases per week to arrive at our borders and we are confident we can catch these with 14-day managed isolation," said Professor Michael Plank, of the University of Canterbury.
"If we went back to pre-Covid travel rates, we would get more like 600 cases per week and it would be impossible to put all arrivals into managed isolation. A return to business as usual is not an option."
Plank said it was important to consider who benefited from loosening border measures - and who paid the economic and health costs of increased risk of community transmission.
"Looking at Melbourne right now, it's clear that the socioeconomically disadvantaged are bearing the brunt of the lockdown," Plank said.
"And in other countries we've seen that the same groups often suffer the worst health impacts. We should not prioritise commercial interests over the most at-risk groups of our society.
"Whatever path we take, we need to tread extremely carefully. If we do decide to loosen our border restrictions, we should do so gradually and start with lowest risk travellers.
"Events around the world show that the pandemic is far from over and that once authorities lose control of Covid-19 it is very difficult to get it back.
"Most countries in the world would gladly trade their Covid-19 predicament with New Zealand's.
"Let's not rush to join them too soon."