The woman, aged in her 20s, is a student at Thebarton Senior College, a school for adult learners which will remain closed for another fortnight.
She is the fifth case linked to the school cluster sparked by another young woman who visited the college while infected.
The latest case has mild symptoms and is in a stable condition.
A woman aged in her 20s has became the latest South Australian to test positive to coronavirus. Pictured is a nurse screening patients outside a clinic in the Barossa Valley
Seventy of her classmates are now in quarantine under police guard at the Pullman Hotel while 1,100 students and staff have been ordered to self-isolate until August 15.
Health officials say they’re doing everything to keep the cluster under control to ensure it doesn’t spark a widespread outbreak.
‘We have not got community transmission in South Australia in any way in widespread form, this is why we are being absolutely over cautious in this instance,’ Chief Public Health Officer Nicola Spurrier said.
The school cluster accounts for five of the eight active cases across the state.
The woman is the fifth case from Thebarton Senior College (pictured) to test positive
Students in hotel quarantine will be offered mental health and social work support.
‘The Thebarton Senior College does have a range of different ethnic and cultural backgrounds of the students attending,’ Professor Spurrier said.
‘These are young people, and vulnerable young people, and we’ll also be engaging some support from social workers as well.’
Thebarton Senior College was due to reopen on Friday before the latest case was confirmed on Thursday afternoon.
The Education Department will release more details on Friday on how students can continue their studies online.
The school now plans to reopen on August 17.
Seventy of the woman’s classmates are now in quarantine at the Pullman Hotel (pictured) under police guard. Pictured are returned travellers at the end of their 14-day quarantine
The latest COVID-19 case takes the state’s total to 457.
‘There is a significantly higher risk of COVID-19 due to current outbreaks interstate. If you have any symptoms of COVID-19, no matter how mild, you need to get tested as soon as possible,’ the latest SA health advice states
The state’s death toll remains at four while 445 patients have recovered.
Meanwhile New South Wales remains on knife’s edge after 12 new cases on Thursday.
NSW premier Gladys Berejiklian revealed millennials are causing a huge percentage of community transmission.
One man in his 20s visited three bars, three restaurants and a supermarket while infected.
Another infected man in his 20s from Newcastle, two hours north of Sydney, visited five pubs in three days and a Newcastle Jets match on Sunday.
‘We’re not saying don’t socialise or don’t go out at all but we are saying please limit your behaviour just in the next few weeks,’ Ms Berejiklian said on Thursday.
‘If you have the virus and you go out five times a week to different places you could potentially be spreading it to five different locations, and then we have to contract trace everybody.’
NSW is battling at least 104 active coronavirus cases – with fears of a full-blown second wave like Victoria.
Two of Thursday’s new cases are under investigation and 10 are linked to known clusters.