Curious mystery of the Australian nurse who became infected with coronavirus TWICE in just three months despite developing antibodies - as two reporters who interviewed her are plunged into quarantine

A young Australian nursing home worker has apparently caught COVID-19 a second time just three months after she was cleared of the virus.

Her fresh diagnosis, extremely rare particularly in Australia, has forced a TV crew into isolation as they interviewed her about border controls.

The reporter and cameraman from Nine News spoke with the woman, aged in her 20s, about border controls after she touched down in Adelaide on flight JQ 776 on Monday. 

The woman tested positive to COVID-19 after the Jetstar flight from Victoria to South Australia, as part of her entry screening process. 

The positive COVID-19 case touched down in Adelaide on flight JQ 776 on Monday. Pictured: A Jetstar plane

Prof Spurrier said two close contacts have been identified following contact tracing. The close contacts sat near the woman on the plane and have been put into hotel quarantine. Pictured: Travellers are seen on a domestic flight during the coronavirus pandemic

The aged care worker originally contracted coronavirus in August in Victoria. She isolated and was cleared of the virus later that month.

She is not showing symptoms, but authorities are yet to clarify whether the woman is shedding the virus or has caught it again. 

The woman is in quarantine at a medi-hotel.   

'Because we are in a particular situation in South Australia with so few cases we are really taking an abundance of caution in this instance and we are calling this an infectious case,' SA Chief Public Health Officer Professor Nicola Spurrier said. 

Prof Spurrier said two close contacts were identified following contact tracing.

The close contacts sat near the woman on the plane and have been put into hotel quarantine.

A TV crew who interviewed the woman at Adelaide Airport are isolating at home after they were identified as casual contacts

The TV crew were identified as casual contacts and are now isolating at home. 

Nine News director Jeremy Pudney said the crew briefly interviewed the woman 'by-chance'.

'At the time, our team members were conducting interviews for a story on travel restrictions, in a public area and at a safe distance,' he told The Advertiser.

'We have been assured by SA Health there is no broader risk to other Nine employees and we are supporting our team members until they're given the all-clear to leave quarantine.'