News Coronavirus ‘Natural experiment’: How SA, Victoria and NSW COVID-19 lockdowns compare

‘Natural experiment’: How SA, Victoria and NSW COVID-19 lockdowns compare

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South Australians could be granted freedom next week, and Victorians may remain under lockdown for another three weeks, a leading infectious diseases expert has predicted.

As for New South Wales, residents are staring down the barrel of another month or two of stay-at-home rules.

“It’s a natural experiment – a tale of three cities,” Professor Adrian Esterman, an epidemiologist at the University of South Australia, told The New Daily.

“You’ve got NSW, which went in very late and not very hard.

“You’ve got Victoria, which went in much quicker and harder, and you’ve got South Australia, which went even quicker and even harder.”

Three lockdowns, three states and three potentially very different outcomes.

South Australia

South Australians have a good chance of getting out of lockdown next week if everyone follows the rules, said Professor Esterman, an experienced biostatistician.

South Australia’s COVID-19 outbreak increased to 14 on Thursday with two new cases.

Under the state’s week-long lockdown, which started on Tuesday night, people are only allowed out for five reasons: To provide essential care, to seek medical assistance, to buy essential food and other goods, for essential work, or to exercise for up to two-and-a-half hours.

“It’ll be very interesting to see how it all pans out, but my gut feeling is South Australia will get out of it pretty quickly,” Professor Esterman said.

“They couldn’t have gone any faster if they tried.”


Meanwhile, Victoria’s lockdown, which started on July 16, could possibly last another three weeks, he said.

“Melbourne modelling shows overall lockdown could be a minimum of 30 days – but possibly longer – starting from the beginning of lockdown,” Professor Esterman said.

But at least the measures appear to be working.

Although numbers have been going up in Victoria, with a top of 26 cases recorded on Thursday, the percentage of people moving around the community while infectious has been low.

For instance, all but two of Thursday’s cases were in isolation throughout their infectious period.

There were limited exposure sites from those cases because both spent little time in the community.

“What I’m seeing is the effective reproduction number has been drastically dropping,” Professor Esterman said.

“Four days ago, it was nearly five and now it’s 1.6, which shows me it’s slowing down.”


Unfortunately, the forecast for NSW isn’t so sunny.

There have now been 1648 locally acquired COVID cases in NSW, since the first case in the Bondi outbreak was reported on June 16.

Unlike South Australia and Victoria, which implemented state-wide lockdowns, stay-at-home orders in NSW only apply in Greater Sydney including the Blue Mountains, Central Coast, Wollongong and Shellharbour.

This is despite COVID cases being detected in regional areas like Orange.

The state’s case numbers surged to a daily record of 124 on Thursday, with warnings of even higher numbers to come.

Making matters worse is the fact that up to 70 of the latest cases were in the community for part of their infectious period, with the isolation status of a further 17 under investigation.

“The best-case scenario in NSW is numbers start to plateau out,” Professor Esterman said.

“We haven’t still the full effects of rigorous restrictions yet. All hell could break loose and we could have another major outbreak, but it looks like it’s approaching the peak of the outbreak in NSW. Hopefully next week, we start seeing numbers come down.”

That could take at least another month or two, he said.

“Generally speaking, if it takes five weeks to reach the peak then it might take five weeks to come out of it.”

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