Victoria’s community adherence to COVID-19 lockdown restrictions during lockdown 6 has prevented around 6000 additional cases of the virus from emerging in August 2021, Burnet Institute modelling has found.

Above: Linear scale of averted cases

Above: Logarithmic scale of averted cases

Premier Daniel Andrews

In his daily COVID-19 update, Victorian Premier Daniel Andrews said the measures, imposed in Melbourne since 5 August 2021, had significantly reduced the impact of the Delta variant outbreak.

“The Burnet Institute have estimated that what we’ve all done, what we’ve all given these last four weeks, has basically prevented around 6000 cases of this virus,” Mr Andrews said.

“That means that every Victorian has also prevented around 600 people being admitted to hospital.”

Mr Andrews said preventing this many cases and hospitalisations over the course of August meant many more cases have been avoided in coming weeks.

“We’ve also avoided thousands more, because once we get to 6000, the numbers just keep doubling and doubling and doubling again,” he said.

Victorian Chief Health Officer, Professor Brett Sutton

Professor Sutton said Victorians' efforts had protected the state’s hospitals from being overrun.

“These restrictions absolutely do work. And all the hard work put in by every Victorian over the last few weeks has protected our health system,” Professor Sutton said.

Professor Sutton said new daily COVID-19 caseloads without restrictions were projected by the Burnet modelling to reach over 3000 by the end of this week.

“The modelling shows we have avoided around 6000 additional cases. But it’s not just those historically avoided cases, it’s the 1700 cases that would have been added today in that modelling. It’s the more than 2000 cases that would have been added tomorrow, those cases increased by about a third every single day,” he said.

“That is a very substantial caseload avoided for people’s avoidable illness, hospitalisation, ICU, and indeed deaths."

Explaining the modelling: Professor Margaret Hellard AM

Burnet Institute Deputy Director, Professor Margaret Hellard AM explained the modelling projected a 34 percent daily increase in cases without restrictions.

“Burnet did some initial analysis models for the Victorian Government trying to get a sense of the impact of the current restrictions. The effective Reff is not less than one still, but it’s having an impact,” Professor Hellard said.

“So, another 1700 cases have been avoided as of 1 September. These are cases averted in addition to the restrictions still in force from 27 July 2021.

“As more and more people get vaccinated the Reff will fall to less than one and case numbers will begin to fall."

Professor Hellard said high case numbers also hindered the efficiency of contact tracing, highlighting the need to gradually ease lockdowns.

“A key issue for Victoria is to be careful coming down the “back of the slope” in releasing restrictions. Too early and too fast and you would get rebound.”

“Also releasing restrictions - any release from lockdown - leads to a longer tail (of cases) but that is balanced against people getting exhausted from long lockdowns and loss of compliance. Also as numbers come down the contact tracing system efficiency improves.”

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