Director-General of Health Dr Ashley Bloomfield is still 'puzzled' about the source of Auckland's latest COVID-19 cluster, first identified on February 14.
A mother (Case B) and daughter (Case A) from Auckland's Papatoetoe were the first to test positive for the virus that has since infected 13 other people.
The mother is an employee in the laundry department of Auckland Airport's LSG Sky Chefs and the daughter is a year-9 student at Papatoetoe High School.
Speaking to a media conference on Tuesday, Dr Bloomfield says it could be possible the daughter contracted the virus first, but he still thinks it was "mostly likely" the case was transmitted through the mother's work.
"We still think some sort of introduction through the mothers' work at the Auckland Airport precinct is the most likely," he says.
"But one thing that maybe speaks against that, is the daughter seemed to have her symptoms onset slightly before the mother, so it's not impossible that that's one thing."
Dr Bloomfield added that a case in MIQ in December had a "similar-ish" genome sequencing as the cases in the latest February outbreak.
"We were looking into the case right back in December, at one of the Managed Isolation Facilities, that had a similar-ish genome sequencing for this B.1.1.7," he said.
"But we've tried hard to see if there's an epidemiological link between that case and these latest cases almost six weeks later without any evidence of community spread, [so] that seems also very unlikely.
"So we're still puzzled about that but we haven't stopped yet."
There are no new positive COVID-19 cases in the community and four in managed isolation, Dr Bloomfield confirmed on Tuesday.
The Director-General says the news is "reassuring" but it's still early on and we're "not out of the woods" yet.
"Based on last week's exposure events listed on the locations of interests page on the Ministry's website, we would expect to start seeing any potential positive cases coming through from today onwards."