Twelve new imported cases of Covid-19 were reported yesterday
- 10 of whom arrived on the same flight from India less than a week ago.
Director of public health Dr Caroline McElnay said the 10-strong group of infected returnees could be the highest number of cases reported in one day from a single flight.
It was possible more travellers aboard Air India's flight AI1354, would test positive for Covid-19, she said.
All 10 returnees, who arrived in New Zealand on September 26, tested positive for the virus around their third day in managed isolation, McElnay said.
"Our most likely theory is that these are individuals that were infected in India before the flight," she said.
They were all spread out aboard the plane, sitting between rows 14 and 41, and genomic testing was being done to help establish a chain of transmission, she said.
It comes after 17 returnees from a single flight inbound from India tested positive for Covid-19 while in self isolation.
That Air India flight from Delhi touched down in New Zealand on August 23.
McElnay said the dozen new cases of Covid-19 at the boarder reflected that flights were returning to New Zealand from places with a higher level of Covid-19.
McElnay says the assumption is that anyone coming into New Zealand may be infectious and every step of the process reflects this.
The worldwide number of Covid cases has now surpassed 33 million, with a death toll of more than a million people. India has the second-largest number of confirmed cases in the world, 6.3 million - the US has had 7.2 million cases. More than 98,000 people in India have died, the third-highest toll in the world.
McElnay said Air India flight AI1354 was flown by Air India, with its international crew in managed isolation when they arrived - which was now standard practice.
"I think they were in for two days," she said. "They were transported to managed isolation, [they] stay there and then get back on a plane and returned back to India."
An Air India spokesman earlier told the Herald the airline was conforming to all the safety and health at every destination point for each and every flight it operates.
"All passengers are screened individually and no passengers with even the slightest symptoms are allowed to board," he said.
"Air India has been taking and will continue to take maximum precaution and adhere to the safety and health protocols for all its passengers and crew for all the flights it undertakes to operate."
McElnay said she didn't have the numbers of how many people had arrived in New Zealand from India since the latest outbreak.
However, the Ministry of Health was looking at pulling together figures to assist with its assessment of high-risk countries, she said.
"We are also looking at pulling the data on recent flights so we can see how that matches up with the level of risk in those countries."
They do not have the results for the India flight yet, however.
"When we get those results, we will be able to look and see if there's anything from the genomic testing that might suggest transmission on the flight," McElnay said.
The Ministry of Health continued to revise the advice it give for managing recent arrivals to the country, including those that are high risk, she said.
There was a range of advice it was pulling together, she said, including whether pre-departure testing needs to take place.
But some of the rapid testing used overseas isn't wasn't as accurate as the testing the ministry preferred to use in New Zealand, she said.
The two other imported cases announced on Thursday were a returnee from the United States arriving on September 26 and a returnee from the Philippines via Taiwan on September 23.
The US returnee tested positive on their third day in managed isolation, while the Philippines returnee was tested because they were a contact of someone with Covid-19.
They tested positive for the virus on Wednesday.
An infant under the age of 1 was included in today's 12 new cases. The oldest was aged 70+.
Children under the age of 12 months old were not always tested for the virus, and nor did they need to be, McElnay said.
New Zealand now has 53 active cases - 42 have been imported, the remaining were in the community. There are 1492 confirmed cases that have been reported to the World Health Organisation.
One person remains in hospital with Covid-19. They are on a general ward in isolation at Middlemore Hospital.
Fourteen people are isolating in an Auckland quarantine facility from the community, which includes five people who tested positive for the virus.