NSW Health says the genome sequence from a Sydney COVID-19 case who works at a Sydney quarantine hotel complex does not match the virus strains seen in recent clusters in Australia.
A Sydney hotel quarantine worker whose COVID-19 infection ended a 26-day streak of no local cases in NSW appears to have acquired the virus from a returned overseas traveller.
Late on Friday afternoon, NSW Health confirmed genome sequencing from the woman's infection did not match the strains seen in recent clusters in Australia, saying it “may be of United States origin”.
“The source of infection may be international aircrew who were self-isolating in the hotel at the time, however investigations are continuing,” NSW Health said.
Airline crews returning from overseas stay in quarantine hotels before turning around and going back overseas.
Earlier on Friday, NSW Health Minister Brad Hazzard said it was "a massive relief" the woman was likely infected at work.
"We will do some more work and report back to the community but is extremely good news for all of us," Mr Hazzard told reporters.
The woman's case, revealed on Thursday, is the only local infection in the state in almost four weeks.
There were 11,128 tests reported in the 24-hours to 8pm on Thursday night with five cases in returned overseas travellers in hotel quarantine.
Deputy Chief Health Officer Jeremy McAnulty says some staff at Sydney's Novotel Hotel who worked last Friday were being tested and placed in isolation.
The positive case's colleagues who worked on 28-30 November have already been tested and her five household contacts tested negative.
The woman's infection sparked widespread alarm on Thursday, with fears Western Australia could withdraw its promise to open its border up to NSW and Victoria from next Tuesday.
WA Premier Mark McGowan says he will take the weekend to assess his options.
However, Queensland authorities say its borders will remain open for now after travel restrictions were lifted on Tuesday.
"The government is keeping a close eye on what is happening in Sydney and our health experts are in regular contact with their NSW counterparts," Health Minister Yvette D'Ath told Queensland parliament on Thursday.
Additional reporting by Evan Young.
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