The Northern Territory’s Covid outbreak has grown to three cases after a woman from Cairns tested positive, but the source of the infections remain a mystery.
The news came as Australia passed the 80% double vaccination dose rate in people aged 16 and over.
The Katherine region was plunged into a snap three-day lockdown on Friday after the Territory recorded the first local case.
The first case was an unvaccinated man in his 20s who tested positive for Covid-19 on Thursday after spending time in Greater Darwin and Katherine. His housemate tested positive on Friday.
Authorities announced on Saturday that a 21-year-old woman who arrived from Cairns on the 29 October, and spent time with the man, had also tested positive. She only became symptomatic on Saturday.
They stayed at Darwin’s Mantra Hotel last weekend, and visited the Monsoons pub and nightclub.
Since 12.01am Friday, Katherine residents have only been allowed to leave their homes for five reasons: to access goods and services, receive medical treatment, provide care and support, perform essential work and exercise.
Greater Darwin is also locked out of Katherine in an effort to contain the spread of the virus.
The NT chief minister, Michael Gunner, said that 1,200 Covid-19 tests had been administered on Friday.
Asked whether the snap lockdown would end on Sunday as planned, Gunner said he was “feeling positive about the fact we have three cases who are linked”.
But, Gunner cautioned, it is still likely there is another undetected case out there from whom the man and woman caught the virus.
“What probably concerns us most at the moment is that we don’t have certainty about how the three people acquired Covid,” he said. “It may be, as we do further work, that one of these has a story we haven’t quite uncovered yet, maybe they are the missing link.
“They could come up in further investigative work but at this stage it would be fair to say that we probably think the missing link is still unknown and that worries us.”
The Queensland health minister, Yvette D’Ath, said health authorities were also working to contact trace the woman who flew from Cairns and tested positive for the virus.
Queensland reported a new local Covid-19 case on Saturday: a woman in her 20s from Goondiwindi, a town on the border of Queensland and NSW.
The woman tested positive while in quarantine, but D’ath warned that she may have had one day out in the community while infectious.
Speaking outside a Bunnings store that was hosting a pop-up vaccination clinic, the Queensland health minister urged residents to get tested.
“The message remains clear, if you have any symptoms and if you have been in the town since the 30 October or anywhere in Brisbane, please come out and get tested,” D’Ath said. “We still have nine active cases.”
Victoria recorded 1,268 new locally acquired Covid-19 cases and seven related deaths on Saturday, bringing the total number of active cases to 16,662.
Victorian authorities confirmed that, as of Friday, there were 651 people in hospital, including 106 in intensive care. Of these, 70 were on a ventilator.
Of the cases in hospital, authorities said 84% were not fully vaccinated, while 96% of those in intensive care had not received both jabs.
In NSW, authorities reported 270 new local infections on Saturday. Three more people with Covid-19 died, none of whom were fully vaccinated.
There were 270 Covid-19 cases admitted to hospital in the state. Authorities said 55 people were in intensive care, 27 of whom required ventilation.
The ACT also recorded 18 new Covid-19 cases, bringing the total number of active cases in the territory to 136. There were only two people in ACT hospitals with the virus, one of whom was on a ventilator.
On Saturday morning, Australia reached a double vaccination dose rate of 80.16% in people aged 16 and over, the prime minister’s office said, with a further 9% having received at least one vaccine dose.
Scott Morrison said the vaccination rate was “another magnificent milestone”.
“This has been a massive Australian national effort and the work doesn’t stop here,” he said. “We are on track to have one of the highest vaccination rates in the world.
“Ninety-nine per cent of Australians aged over 70 have had a first jab and over 90% have had a second. That is just extraordinary.”
But vaccination rates vary significantly state-to-state, and are critically low in some communities.
As of Friday, the ACT was leading the way in terms of vaccinations, with almost 95% of over 16-year-olds having received both jabs.
A total of 89% of those over 16 in New South Wales, 83% in Victoria, 77% in Tasmania and 66% in Queensland were fully vaccinated.
By comparison, only 65% of residents over 16 had received two doses of a Covid-19 vaccine in Western Australia and the Northern Territory.
New data from the National Aboriginal Community Controlled Health Organisation (NACCHO) shows concerning low vaccination rates in Indigenous Australians, two months after “surge” efforts from authorities to target 30 Aboriginal communities nationwide.
Analysis of the most recent data by Guardian Australia shows that the surge effort has produced some positive results, but the gap between the Indigenous and the overall vaccination rates remains high.
Overall, there is a 19 percentage point difference between the Indigenous and overall first-dose vaccination rates in most of the priority areas.
