The exact source of the new Auckland community Covid cases is the "big unknown" and there could be other cases, epidemiologist Michael Baker says.
Auckland is in alert level 3 lockdown and the rest of the country in level 2 in response to the community cases announced yesterday afternoon.
Prime Minister Jacinda Ardern has confirmed the community cases are the UK variant of the virus, according to genomic sequencing. She said it was unlikely to have been a breach from managed isolation and quarantine facilities.
The cases are a mother, father and daughter who live in the South Auckland suburb of Papatoetoe. Another household contact has tested negative. The mother works for laundry and catering company LSG Sky Chefs, which services planes at the airport.
"It's very much a repeat of the Auckland August outbreak. Hopefully it will be much smaller and more contained," Baker told First Up. "But it's the same scenario where you have cases in the community, you don't have a direct certain link to the borders."
The concern is not knowing exactly where the outbreak came from, Baker said.
"And that means there could be other cases in the community - there must be - who link this family to someone at the border."
The best outcome would be if that was a small number of cases, and testing will work out if that is the situation, he said.
"[The mother] is not a frontline border worker. The big unknown is how she got infected, assuming she was the first case in that household - we can't make any assumptions.
"There's still no documented examples of people being infected through what we call fomites - that's surfaces or objects.
"It's still a fairly unlikely form of transmission."
Baker said the new variants of Covid-19, such as the UK strain, have the same mode of transmission, and it's the same method to stop the spread. "It's just that we'll have to work harder because it's a more infectious variant."