Authorities are concerned the two 19-year-old women, from Logan and Acacia Ridge, may have unknowingly spread the disease in their local communities in the eight days before they tested positive.

They are trying to identify contacts of the women by retracing their movements, which have been mainly in the Logan and Springfield areas, south of Brisbane.

This includes in shopping malls, restaurants, a church and a school, where one of the women works.

The pair returned to Brisbane on July 21 from Melbourne via Sydney on Virgin flights VA863 and VA977.

The Logan woman then went to work at Parklands Christian College, also in Logan.

She was last there on Thursday, four days before she tested positive.

Queensland Health has issued an alert for the following venues and times:

What happens when someone tests positive at a school?

The school has been closed indefinitely for cleaning and disinfecting and all events are cancelled in the meantime.

Queensland Health is working to identify close contacts of the infected person.

Staff members in direct contact with the woman have gone into isolation.

The school believes the employee had “limited contact with students and the wider college community”.

What will the school’s testing clinic look like?

A fever clinic has been set up at the school.

The clinic, set up by a state public health unit, will involve testers in protective equipment.

They will take nasal, throat or mucus swabs for testing — a brief but eye-watering procedure.

The samples are sent to a laboratory.

Clinics try to move people through rapidly.

How soon are people expected to attend the clinic?

From this afternoon anyone who has symptoms or concerns can be tested at the clinic.

They’ll have to isolate, right?

People may be advised to isolate until their test results are confirmed, which could take several days, or until any symptoms they have are gone.

The two women who tested positive are being treated in the Princess Alexandra Hospital.

Do kids and adults who attend the school need to be tested?

Yes. Deputy Health Minister Steven Miles said anyone with any concerns on the southside of Brisbane should get tested, particularly people in Logan and Springfield Lakes.

Should families of people at the school go into isolation?

This depends on whether people have had direct contact with the infected person.

Close contacts in households of both the Logan woman and her travel companion from Acacia Ridge have been ordered into quarantine.

What happens if you mixed with students through sports, church?

The most prudent thing is to get tested and self-isolate until your results are known.

This lowers the risk of the virus spreading further in the community undetected.

What’s happened in other schools interstate?

Just yesterday in NSW, a student tested positive at Bayanami Public School in Parramatta.

This school will have a similar response — the school will be closed for cleaning while authorities scramble to trace the child’s contacts.

People in the region who develop symptoms are urged to get tested.

The aim is to avoid a coronavirus cluster, such as the one that emerged at Melbourne’s Al-Taqwa College earlier this month.

It became Victoria’s biggest cluster with more than 113 cases and was linked to the spread of the virus in public housing blocks that were then subject to a sudden lockdown.

Does this raise the risk Queensland will close its borders again?

The Palaszczuk Government yesterday tightened border restrictions by declaring Greater Sydney a COVID-19 hotspot.

This bans Sydney residents, and anyone who has been there, from entering Queensland.

The exception is returning Queensland residents, who will be forced to quarantine at a hotel for 14 days at their own expense.

There’s now a criminal investigation into whether the women lied on their travel declarations to get through the border without being quarantined.

The State Government is expected to advise the community of any other locations that the women attended and where there may be concerns.

– ABC / Josh Robertson