The transmission of Covid-19 at a Brisbane hotel that infected a flight attendant could be a "world first", according to Australia's chief medico.
A woman aged in her 30s who arrived from Portugal tested positive to the virus on Saturday after she was released from 14 days quarantine. Between leaving the hotel and being contacted about her positive result she spent four hours in the community.
Genomic sequencing has since linked her strain of the virus with that of another flight attendant, who arrived into Brisbane on a completely different flight and was staying on a different floor of the Four Points Hotel.
Both people have the Alpha variant.
The woman had been tested for Covid-19 three times during her stint in quarantine.
Investigations are ongoing into how the woman contracted the virus, but chief medical officer Paul Kelly said the "more logical explanation" would be that a staff member acted as an intermediary between the two cases.
"It is unusual. In hotel quarantine, the transmission we've seen have been very close rooms and on the same floor, but there are staff that moved from floor to floor," he said on Monday.
"If I was a betting man, (it has) something to do with staff movement.
"It appears the transmission was from a higher floor to a relatively low floor, it would be a world first."
All staff members at the Four Points Hotel are being retested.
Queensland chief health officer Dr Jeannette Young said she was "confident" staff weren't involved in the transmission because they are tested "every single shift".
"There is no doubt that she has acquired it in the hotel, or at some point when she's come into contact with that person," Young said.
"All that work is happening."
Young said anyone who was at Brisbane Airport DFO between 4pm-4.30pm, Brisbane City from 5pm-6pm, and at the Portuguese Family Centre at Ellen Grove between 7pm-7.30pm should contact health authorities.
Anyone who was at the DFO Cotton On Store between 4.10-4.30pm on Saturday needs to self-quarantine immediately.
There were five cases detected in hotel quarantine on Monday. There are 32 active cases in the state.