It's imperative that health officials are able to pinpoint how Auckland's latest case of COVID-19 contracted the virus, says leading microbiologist Dr Siouxsie Wiles, as it is currently unclear how the Papatoetoe High School student became infected.
On Tuesday, it was announced that a ninth person connected to the Auckland cluster had tested positive for the virus in the community. The student is a casual-plus contact, which suggests they did not come into close contact with an existing case of COVID-19.
On February 14, health officials confirmed that a Papatoetoe family - a mother, father and child - had tested positive for the virus. After it was revealed that the child was a student at Papatoetoe High School, the school community was asked last week to seek a test.
An additional five cases - referred to as Case D, Case E, Case F, Case G and Case H respectively - were subsequently detected and linked to the original trio. The latter four are household contacts of Case D, who is also a student at the school.
COVID-19 Response Minister Chris Hipkins confirmed on Tuesday that the latest case, who lives in a household of six, was first tested for the virus on Monday despite being asked to seek a test last week. He could not confirm if the family had been adhering to self-isolation.
Speaking to Newshub, University of Auckland associate professor Dr Siouxsie Wiles said understanding how this latest case contracted the virus is "really important".
"What I think is really important about this case is understanding how transmission happened," she said.
This new development will be useful both locally and internationally in regards to understanding transmission in a school setting, Dr Wiles said, a topic of intense interest overseas as countries attempt to re-open schools after months of lockdown.
"This cluster will help us understand more about transmission in a school setting and how exposure leads to transmission."
She reiterated that although wastewater testing does not suggest an outbreak is circulating in the community undetected, it's important health officials investigate the possibility of incubation among those contacts who have tested negative.
"What we need to know is whether people who have already tested negative [have been] incubating the virus, and may potentially test positive around about now," she said.
"The question is are there any others popping up around now too."
International evidence suggests incubation can last between two to 10 days, however in some cases, incubation can be as long as 20 days.
Dr Wiles said there is currently not enough information to suggest a rapid move back up the alert levels.
"We have contained outbreaks without moving up alert levels before," she said.
"So in a community like this, where the school is on-board and helping get the right information out, there's no reason why we couldn't use contact tracing, testing and isolation to get it under control.
"What's going to be interesting now is to see whether there are any other cases."
