Authorities say incoming Covid-19 community test results following the Auckland cases are encouraging, but caution in the next few days will be crucial.
Director-General of Health Ashley Bloomfield says it's important for parallel chains of transmission to be uncovered if they existed. Photo: RNZ / Samuel Rillstone
A surge in testing has yet to discover any spread to close contacts or further into the community.
Director-General of Health Ashley Bloomfield told Morning Report that was positive, but it was important for parallel chains of transmission to be uncovered if they existed.
"The key thing we're trying to rule out is, first of all, have any of our existing cases passed the virus on to someone, either at the school or in the workplace. Now the testing so far is reassuring in that case."
"It's really important here to remain open minded" - Director-General of Health Ashley Bloomfield
The daughter in the Papatoetoe family at the centre of the recent community cases was the first to report the onset of symptoms, but it was still unclear if she was the index case.
"Whilst, yes, the mother works in the Auckland Airport precinct and, whilst arm's length removed, has got an association with incoming flights through being part of that laundry, it's really important here to remain open-minded," he said.
"So, we're very interested, of course, in the testing from the school to make sure that if indeed the daughter was the index case that we are identifying where that might have come from."
The mother, father and daughter - who all tested positive - have been moved to quarantine, while another household contact who has tested negative remains in isolation at home. Bloomfield said the family was doing well.
More than 3000 people were tested across the Auckland region yesterday, focusing on close contacts and those who had visited places of interest.
Read more on the latest Covid-19 outbreak:
- Follow RNZ's live blog for the latest Covid-19 updates
- View updated locations of interest here
- Alert Level 2 and Level 3: What they mean
A pop-up testing centre at Papatoetoe High School. Photo: RNZ / Liu Chen
"This is the thing we're trying to find out, really are there parallel or onward chains of transmission in the community. I should say that our sense is that we would have picked up at least someone else, through the regular testing of anyone with symptoms," Bloomfield said.
Wastewater testing in the area last week had also returned an encouraging result.
"ESR has been doing some quite regular wastewater testing, the last result from that was on the 10th of February and that didn't show any virus in the South Auckland area."
More wastewater testing would be carried out this week, he said.
On saliva testing, Bloomfield said this was being rolled out across some managed isolation and quarantine facilities and cost around the same as a nasal swab test.
"We have talked to Rako [Science] about their testing, which is saliva based, and the results they have are from the US, which we're still treating with some caution about whether it's going to be as accurate as the swabbing," he said.
"So we will be watching with interest any further work they do and any results they have from that."
Dr Janet Pitman, lead academic on the Rako Science advisory board, told Morning Report the lowest level of virus the test could detect in a sample was similar to that of the Ministry of Health's nasal swab test.
In a blind test using 150 known positive and negative samples, it showed a 100 percent success rate in distinguishing between the two, she said.
Pitman said the saliva tests being used by the government were "very different" to the Rako version.
"The University of Illinois have now done 1.3 million tests using this Rako Science test ...they are quoting a 98 percent accuracy" - Dr Janet Pitman