Deputy chief public health officer Dr Michael Cusack told ABC Radio Adelaide this morning the case does not represent unknown community transmission, but SA Health contact tracers are still trying to determine the exact link.

There was an update from authorities at 1.30 this afternoon. Read the latest news here.

“The link that we’re looking at, at this stage, is the pizza bar, but… the precise linkage in terms of dates, times and so forth, we have yet to identify,” he said.

“We believe that the student was at the school on Monday when they were likely to have been infectious.”

Chief public health officer Professor Nicola Spurrier said the girl had exposure to COVID-19 when she picked up a pizza on November 14, during an infectious period.

Two medi-hotel staff are known to have worked at the pizzeria during this period, including the Spanish man whose misleading information was blamed for last week’s lockdown.

SA Health last night issued an alert advising anyone who attended the Woodville High School on Monday November 23 to immediately isolate with all members of their household until further notice.

The school is closed today to undergo deep cleaning and to allow SA Health to conduct contact tracing and risk assessment.

Health authorities are now advising anyone who visited the Woodville area over the last few days to isolate and get tested if they develop coronavirus symptoms.

“Anybody at the school who develop symptoms, we would encourage that they get tested as soon as possible,” Cusack said.

“I think we’ve been able to get the information that we need … but this is an evolving situation.”

Education Department executive director Anne Millard told ABC Radio there were over 900 students at Woodville High School who have been forced to isolate at home with their families.

They join the approximate 4300 people who were already in quarantine after coming in contact with positive cases.

The Education Department is waiting for SA Health to advise when the school can reopen.

Cusack said SA Health was unsure whether the student caught public transport over the past few days.

“That’s going to be a key piece of information for us,” he said.

“If a person was infectious at school on Monday it would still require an incubation period before the secondary contact then became infectious themselves.

“We will need to move very quickly on to identify who are the close contacts, are they infectious and where have they been.

“Once we’ve established that ring around the person who is infectious themselves and who isn’t we can be a lot clearer in our public messaging.”

The number of COVID-19 cases linked to the cluster in Adelaide’s north has now risen to 31.

But Health Minister Stephen Wade told ABC Radio Adelaide there was “no suggestion” that restrictions would change in light of the increasing tally.

“I’m a politician not a clinician but if I was imagining what Nicola would say, I think Nicola would say this is exactly what we were expecting,” he told FIVEaa Radio this morning.

“Two-thirds of our cases were identified in the first two days of this cluster (and) since then we’ve had an average of one or two cases a day.

“It’s not surprising that people in the community are picking up COVID.”

SA Health has announced drive-through testing sites on Friday and Saturday will be open from 6.30am to 11am, with the Victoria Park site reopening in the evening from 8pm to midnight, in response to forecasted hot weather.

Indoor testing sites, such as those at hospitals, will not change opening hours.

Wade said he would discuss opening a pop-up testing site in Woodville at a leadership meeting this morning.

“We certainly want to make it as easy as possible (to get tested),” he said.