It was the inevitability many Victorians feared, but when Premier Daniel Andrews announced another round of lockdown measures, the six-week ruling came as an unexpected shock.
Premier Andrews acknowledged authorities “could have gone for a shorter period” but ultimately the life cycle of the virus had determined the decision to shut Melbourne and Mitchell Shire for a full six weeks.
“The life cycle of this virus is about the 14-day period,” he said.
“The six weeks means we have three of those full cycles.”
A six-week lockdown would allow for the lag between being exposed to the virus and getting a positive test, according to infectious diseases doctor Trent Yarwood.
“The incubation we think, for most people, is less than one week, but the public health guidelines say that you should consider exposures up to a fortnight,” Dr Yarwood said.
He said the time frame recognised that public health responses could take a while to kick in.
“All the transmissions reported today happened a week ago,” he said.
“There is no rule book to guide how to do this. It’s trial and error.”
Experts said the lockdown was necessary as the rising cases in Victoria were due to community transmission of the virus and not from returned travellers coming back from overseas.
It means hundreds of people may now have it — potentially passing it on to others — but not test positive until next week, or even the week after.
“I can assume that what they want to do is a combination of playing it really cautiously with that exposure period, plus allowing some time to really make sure that the interventions have worked, then to have time to review it and work out how to ease restrictions again in a safer way,” Dr Yarwood said.
Victoria never achieved zero cases
As the daily number of people testing positive soared towards 200, public concern over further postcode lockdowns was palpable.
The decision will be difficult for business owners who thought they’d be ramping up — not scaling back — from July, but it may give Melbourne a better chance in the long run.
University of Melbourne epidemiologist Professor Tony Blakeley said four weeks may have been enough to control the spread of COVID19, but six weeks of lockdown would help bring the state closer to complete elimination.
“Four weeks would have been enough I think to have probably got control, which does mean within six weeks we could have a go at elimination,” he told 7.30.
If we don’t eliminate the virus, this will happen again and again until we get a vaccine.”
“The first thing we need to do is get control of this current outbreak,” he told 730.
“That’s the focus for the next two to three weeks.”
Dr Yarwood was satisfied authorities were making lockdown decisions based on the best possible scientific evidence.
“The challenge for Victoria compared to the rest of Australia is that they never got to zero cases, like other states did,” he said.
“They always had a few cases and the population density is much greater.”
Hoping to prevent ‘a tragedy’
Dr Yarwood said the decisions, including the latest lockdown, were driven by the chief medical officers of each state and territory who sat on the Australian Health Protection Principal Committee.
The Premier admitted the new lockdown would be very challenging.
“Without a vaccine, without a cure, without better treatment, if we didn’t take these steps, I would not be standing at this podium saying there are 191 cases,” Mr Andrews said.
“I’ll be reporting hundreds and thousands more than that. We will have thousands of people in hospital and we will all know what that means.
“That means tragedy.”
Experts said with the high levels of community spread of COVID-19 in Victoria, a full six-week lockdown was needed to stop the virus spiralling out of control.
“There is a unanimous view that this is required to avoid absolutely catastrophic outcomes,” Chief Health Officer Dr Brett Sutton said.