The best case scenario for Greater Sydney’s lockdown as cases soar

Sydney’s numbers keep getting worse but certain crucial figures will provide a hint about how long the lockdown is likely to last.

As Greater Sydney again records another record day of Covid infections, key figures on Wednesday and Thursday will likely decide the future of its lockdown.

Authorities were forced to tighten restrictions on Friday as previous rules were unsuccessful in controlling the transmission of coronavirus. Case numbers again soared to 77 cases on Sunday and 112 cases on Monday.

NSW Premier Gladys Berejiklian conceded the city would probably not be easing restrictions on Friday as scheduled.

“Given where the numbers are it is not likely, in fact, almost impossible for us to get out of lockdown on Friday,” she told reporters on Monday.

“We will be able to provide you further information as soon as that comes to hand

“The length of the lockdown will depend on our ability to come together and to follow the health advice across the state.”

La Trobe University epidemiologist Associate Professor Hassan Vally said the numbers on Wednesday and Thursday would be crucial in understanding how much longer lockdown would go for.

“We’ve had a bit of experience in how long it takes to get transmission under control and at this stage everything is heading in the wrong direction,” he told news.com.au.

“At best you might get a turnaround on Wednesday or Thursday, which is five days after they ramped up restrictions (on Friday).

Prof Vally said the important question over the next few days would be how much numbers were growing, and how quickly they turned around.

“It’s really got to be a day by day analysis about what the numbers are telling us, that dictate what we do.

“Right now it’s clear to everybody that the numbers are going in the wrong direction. I hope by Wednesday we’ll see that stabilising and turning around.”

He said predictions were not easy to make because the virus circulating in Sydney was the more infectious Delta variant, but he said there was a possibility the lockdown would continue for three to four weeks, which experts such as University of NSW Professor Mary-Louise McLaws, an adviser to the World Health Organisation, are now predicting.

“Even if that’s not the case, we’ve seen the way authorities relax restrictions … is that they ease them off slowly, so either way Sydney will experience some sort of restrictions for quite a while to come,” Prof Vally said.

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A man walks down an empty Bankstown City Plaza. Picture: Toby Zerna

There are already calls to tighten restrictions in Greater Sydney, with the Burnet Institute expected to release modelling today that shows even the current rules are not strict enough to bring cases down.

Prof Vally believes there is an argument for introducing stronger restrictions now, even before the impact of Friday’s tighter restrictions is known.

“There is an argument for tightening, based on what we’ve seen work – which is going hard and going early and just crushing transmission. We’ve see going hard actually does work.

“The risk in what we’re seeing now is that transmission can grumble along and take time to bring under control.”

Prof Vally said the most obvious measure would be closing more non-essential retail. Other options could include a 5km travel limit. Both these methods helped to bring Melbourne’s outbreak under control last year.

“The harder, the better, and the more you crush transmission. In theory, the shorter the period you have restrictions,” he said.

The “best case scenario” would be for the impact of Friday’s tighter restrictions to kick in by Wednesday or Thursday.

“You would start to see lower numbers of new cases and much lower numbers of cases circulating in the community before they were detected,” Prof Vally said.

“If we start to see this, we can have confidence that the restrictions are working.

“How quickly we can get transmission levels under control is a more difficult question. I think we are talking about weeks.”

Prof Vally pointed out that 33 of the 77 cases announced on Sunday had been circulating in the community while infectious.

“That’s close to 55 per cent of cases spreading the virus, which is why they were predicting higher numbers (on Monday).

“It’s a pretty dangerous and unstable situation – it’s definitely scary times for NSW right now.”

The NSW Premier said the number of cases in the community while infectious would have to be “as close to zero as possible” before Health would advise the government on an end to the lockdown.

Asked whether she agreed with experts the lockdown would last another three to four weeks, Ms Berejiklian said: “that depends on how quickly our community responds to those cases that are infectious in the community. It is really up to us”.

She said at least 34 of the 112 cases announced on Monday had been infectious while in the community.

But she said there appeared to have been a “massive drop in mobility” in the past few days that showed people had heeded the warnings.

“Once we see the impact of that we will have a better assessment of the time that we think the lockdown will be in,” she said.

While Prof Vally did not expect cases numbers to spin out of control due to the fact that there were restrictions in place, it’s possible the state could keep “heading in the wrong direction”.

“This would be an indication that we need to go harder, or for some reason current restrictions aren’t working so they could tinker with them.

“Optimistically I don’t think cases will get out of control but anything is possible.”

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