The number of new recorded COVID-19 cases in South Australia has jumped by more than 3,000 compared to last week's figure, with health authorities also reporting another seven deaths linked to the virus.
In its weekly update, SA Health reported 6,867 new cases over the past seven days — significantly more than the 3,797 reported last Friday — while the number of current active cases has also increased, to 5,185.
"The increase over the last week is the highest for any state and territory," University of South Australia epidemiologist Adrian Esterman told ABC Radio Adelaide's Afternoons program.
The rise in SA's caseload coincides with a wave of the virus across the nation, with the state's Chief Public Health Officer Nicola Spurrier last week declaring "we're definitely in that wave".
The seven people to die ranged in age from their 50s to 100, SA Health said.
But it added that 10 cases had been removed from the total number of deaths — which currently sits at 1,058 since the start of the pandemic — after it was determined that they were "found to be unrelated to COVID-19".
As of Thursday night, there were 83 people in hospital in South Australia with the virus, including seven in intensive care and two on a ventilator.
Professor Esterman said there were three reasons why he was "expecting these big increases in case numbers".
"The first is that many of us had our last dose of vaccine more than six months ago," he said.
"Secondly, we've got these new sub-variants which we know are more transmissible.
"Thirdly, we've removed all our public health measures and we don't have any brakes to put on transmission at the moment."
Professor Esterman said while he thought it was unlikely to occur, he would like to see a return of mandatory mask-wearing including in various healthcare settings, shops and on public transport.
"We've got people now just wandering onto trains and trams who are infectious [and] don't give a damn," he said.
Extra pressure on the state's health system has already been highlighted this week, with Flinders Medical Centre having to cancel almost two dozen elective surgeries to boost capacity amid growing numbers of furloughed staff and COVID-19 cases among patients.
"COVID numbers are back on the rise again, largely in accordance with expectations, but that nonetheless brings pressure to the system and of course elective surgery flexibility is an important tool," Premier Peter Malinauskas said.
"When we see those numbers go up, we know there's more pressure on the hospital system on its way.
"The pandemic isn't over, we are in a different phase, we're also in a different position to be handle growing case numbers through vaccines [and] the fact that a majority of South Australians have already had COVID."
