The Air New Zealand crew member who tested positive was "incredibly diligent" in taking precautions during a layover, the airline's chief medical officer says.
Fourteen Air New Zealand crew are being tested and made to isolate after the flight attendant was found to have Covid-19 after arriving home from Japan.
That crew member is in the Jet Park quarantine facility, and her family members have all tested negative and are isolating at home.
Air New Zealand chief medical officer Dr Ben Johnston said the flight attendant was doing very well.
"I've spoken with that person earlier today. They're completely well," he said.
"And so far, no additional cases. The additional 14 people… are all in isolation, the majority of their test results back and negative, although some are still awaited.
"I understand they need to have further testing after that, that's under the control of public health authorities who direct these investigations and control of these contacts. But I understand they will have further testing."
The flight attendant had recently returned home from Japan, which is not considered a high-risk route under Air New Zealand's Covid-19 protocols.
"They're permitted to go home, they have to comply with the surveillance testing requirements," Dr Johnston said.
"So they had a test on arrival and then the further test on 6 March, which is where the case was picked up."
The crew member was then moved from their home to the Jet Park quarantine facility.
Dr Johnston said Air New Zealand did not enforce an isolation period for cabin crew as the risk was not the same across the organisation.
"We have duties that span the full range of risk from… nearly zero risk with our domestic operations, through to very low risk to and from Australia, and then varying levels of risk at different ports.
"The level of risk depends on the Covid-19 risk of prevalence in that destination. It also depends on that level of confidence about that person being able to move through the airport to the hotel and stay in the hotel."
Johnston said the protocols have worked, saying in the past 11 months Air New Zealand only had three cases of staff with Covid-19 – two of which were in MIQ when they tested positive.
"To put that in context over that period of time there's been more than 5000 international flights operated. So the risk we're talking about here is incredibly low."
He said crew members' movements were not directly traced when they were in layover, but people did keep in regular contact with them.
"We make sure they're fully informed, we ask them to sign declarations showing that they understand what their obligations are. We ask them to do that regularly. We regularly refresh them on their on their obligations and of course we always look very deeply into any event such as this.
"In this particular case, this flight attendant has been incredibly diligent in what she's done.
"She's done things like taking her own food with her, taking her own cutlery, taking her own glass to drink from.
"And so far we just haven't been able to find a clear event which caused this transmission."
He said he would be interested to see the results of genomic testing on Tuesday.
Air New Zealand's risk assessments for places they fly to are decided by the Ministry of Health. Johnston said the risk assessment of other ports is reviewed regularly.
Meanwhile, the government has revealed it is getting another 8.5 million doses of the Pfizer Covid-19 vaccine. Combined with what it already has, it is sufficient for five million people to the two jabs needed.
Jacinda Ardern says the decision to make Pfizer Aotearoa's primary vaccine provider is based on the fact the vaccine is around 95 percent effective.