He warned that if the virus kept spreading at the current rate, it would inevitably reach older and more vulnerable people and cause more deaths.
“It is hard to get in there with a message to people who suffer more mild illness,’’ Professor Sutton said. “But I would say to anyone who is young, from teenager to 20s or 30s, don’t just think about your family, think about what this might mean in terms of transmission through your entire community and what the consequences might be for those who are most at risk.’’
Premier Daniel Andrews said that if people did not adhere to social distancing rules, it would jeopardise the state’s recovery.
“We will get to a point, once we get on top of this, where there can be further opening up,’’ he said. “But every day where even small numbers of people do the wrong thing puts that opening up at risk and it certainly puts it further away.”
Since June 8, the last day on which Victoria recorded zero new COVID-19 cases,109 of 341 new confirmed cases have been in people aged between 18 and 30. This compares with 78 in May and 85 in April.
The demographic shift of COVID-19 in Victoria from the first stage of the pandemic mirrors what US health authorities are observing in states where the disease is currently spreading the fastest.
In Florida, where a surging caseload has forced the closure of bars and beaches at the height of summer, the median age of all cases has dropped from 65 in March to 35 in June, with 15 to 34-year-olds accounting for nearly one-third of new cases.
In Arizona, another COVID-19 hotspot, government statistics show that in Maricopa County, the local government area which takes in Phoenix, nearly half of all cases are aged between 20 and 44. A similar pattern has emerged in Texas.
The good news in Victoria is that although the COVID-19 caseload is steadily increasing, hospital admissions are not. As of Sunday there were just seven COVID-19 patients in Victorian hospitals, including one in intensive care.
Professor Sutton warned this could change.
“In the same way we have seen the US cases take off like nothing else but deaths have continued to fall, there has been a transmission to a younger population,’’ he said.
“We have seen a greater proportion of our recent cases in the 20 to 40-year age group. We are not going to see those people requiring hospital but the danger still is there.
“If we continue to have cases at 40, 50 a day, unfortunately we will see deaths associated with it because it represents a lot of transmission and there will be a lot of vulnerable people who will be potentially exposed.’’
On a cold, sunny Sunday in Melbourne’s CBD, young people spoken to by The Age said they were observing social distancing but saw plenty of other people who weren’t.
“You know a lot of people that don’t take it quite as seriously, but at least the people I’m in contact with take it seriously,’’ said Carlton D’Silva, 26.
Jason Krowitz, 23, said he had wanted to attend the Black Lives Matter rally but avoided it to protect his housemates, who are immunosuppressed.
“As sceptical as I was of the COVIDSafe app, I downloaded it and use it all the time,’’ he said. “It’s not for me, it’s for them.’’
Most of the current cases in Victoria can be traced to quarantine hotels, where returned travellers are accommodated, and outbreaks within large family groups in the northern and western suburbs.
Mr Andrews said while an “army’’ of door-knocking testers had been mobilised to trace and contain known outbreaks, the government response on its own would not contain the virus.
“Everyone is deeply frustrated, everyone wants to go back to normal, but just because you want it to be over doesn’t mean it is over,’’ he said.
“There are thousands and thousands of people working day and night. Please work with us. Please do the right thing. Please follow the rules. Please get tested.”
Some 50 Australian Defence Force Members have been assisting with testing at five sites across Melbourne since arriving late on Friday.
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Lieutenant-Commander Thomas Miller from the navy said the Melbourne Showgrounds had been “one of the busier centres” for COVID-19 testing in Victoria throughout the weekend, with a consistent stream of cars filtering through the site.
With Ashleigh McMillan
Chip Le Grand is The Age’s chief reporter. He writes about crime, sport and national affairs, with a particular focus on Melbourne.
David Estcourt is a court and general news reporter at The Age.