Coronavirus: Only 40pc of Sydney people staying at home, modelling says

Scientific modelling shows an alarming number ignoring health orders, and a lockdown of over two months at that rate.

People exercising along the Milsons Point boardwalk on Friday in Sydney. Picture: Getty Images

Modelling by scientists at the University of Sydney has estimated that only 40 per cent of people in Sydney are staying home, and predicts it is unlikely that NSW will be able to reduce case numbers of the Delta variant at current lockdown settings.

The modelling predicts that if 80 per cent of Sydneysiders complied with public health orders and stayed home, it would take a month for cases to reduce from the peak to below 10. However, if compliance fell to 70 per cent, it would take more than two months to bring the outbreak under control.

Covid-19 modeller and director of the University of Sydney’s Centre for Complex Systems, Mikhail Prokopenko, says Sydney’s current level of social distancing is inadequate for outbreak control.

Professor Prokopenko said that to see a drop off in case numbers in one month, Sydney residents must reduce their social interactions including shopping to one tenth of their normal activity.

“Our estimation shows that with only 40 per cent of people staying at home, that would be inadequate even for a less transmissible variant, and for Delta it doesn’t even scratch the surface. It’s inadequate to bring the incidence down.

“If that trend continues then the incidence numbers will not start reducing, they will keep growing and then the suppression will not be achieved and the lockdown will continue.

“What would be required would be for everyone to reduce their shopping frequency or duration to just 1 out of 10 typical trips or hours. So, if someone spent 10 hours a week doing the shopping, now it needs to reduce to just one hour of shopping a week,” Professor Prokopenko said.

“The same goes for chatting with neighbours, and other activities which involve being around people outside your household.

“Crucially, 80 per cent of social distancing also means that many services currently deemed essential would need to be included under the lockdown restrictions.”

Professor Prokopenko said that when he ran his modelling, he was shocked at the level of non-compliance with public health orders.

“I totally was surprised because our previous model during lockdown last year was showing that we immediately switched to 80 if not 90 per cent compliance,” he said. “I thought it would be something in this interval.”

Cars enter for Covid-19 testing at the Fairfield Showground drive-through clinic, in Sydney. Picture: NCA NewsWire/Bianca De Marchi

He said many of the 60 per cent of people who were active in the community were going to work. “Some of them may have a legitimate reason not to stay at home because they’re engaged in essential services,” Professor Prokopenko said. “Maybe 30 per cent are doing essential services and maybe the other 30 per cent are simply not complying.”

The University of Sydney modelling comes after similar modelling completed by the Burnet Institute found that tougher restrictions would likely be needed to control the outbreak of the Delta variant in NSW.

The Burnet Institute’s modelling found that if the current restrictions in NSW are kept in place, it would take at least two months for daily cases to fall below 40 and many more months for cases to reduce to zero.

NATASHA ROBINSON