The state health department on Wednesday night confirmed the virus was transmitted in quarantine, saying the two sets of guests with the same strain arrived from different countries at different times.
In Perth, recent guests from the same floor as the transmission will be re-tested and those who were in the immediately adjacent rooms will be self-quarantined for 14 days.
“The Department can confirm the virus was transmitted in hotel quarantine at the Mercure Hotel Perth, as two sets of guests, in rooms opposite each other, had the same sequence of virus – despite arriving from different countries at different times,” the WA Health Department said in a statement.
“All other guests who previously stayed on the same (sixth) floor during this time and have been released from the hotel facility tested negative prior to release.
“These guests will be re-tested and directed to self-isolate until cleared by the public health team.”
The department noted hotel staff underwent daily testing and none had yet tested positive.
“While similar transmission in hotels in other jurisdictions has not resulted in community transmission, the community must always remain vigilant,” it said.
“The threat of COVID-19 remains real.
“This is a timely reminder that if you are experiencing symptoms, please go and get a COVID test.”
Also on Wednesday, NSW Health launched an investigation into how three returned travellers, two of whom are related and all of whom arrived on April 3 on the same flight, all tested positive to the South African strain of the virus.
The two family members were in connecting rooms on the hotel’s 10th floor, while the third person was in an adjacent room.
They all tested negative for their day two swabs in quarantine but later tested positive on different days.
NSW Health is contacting returned travellers who were on the same floor of the hotel from April 7-12.