Covid 19 coronavirus: How Melbourne can avoid another lockdown

Cars line up outside a drive through Covid-19 testing facility at the Melbourne Showgrounds on May 25, 2021. Photo / Getty Images

Melbourne could be on the cusp of another lockdown after another six coronavirus cases were discovered overnight.

The Herald Sun has reported that the Victorian Government is considering a five-day circuit breaker but the decision could go "either way".

A leading epidemiologist has told news.com.au he is "nervous" about the extent of the current outbreak and a lockdown could be on the cards.

Acting Premier James Merlino confirmed there were now 15 cases linked to a current cluster spanning several households and a workplace, with numerous exposure sites across many different parts of Melbourne and Bendigo.

"These cases are linked and that's a good thing but we are very concerned by the number and by the kind of exposure sites," Merlino told reporters today.

The list of exposure sites that people visited while potentially infectious continue to grow, and include one of Melbourne's biggest shopping centres, pubs, gyms, hairdressers, and popular supermarkets in suburbs like Carlton, Epping, Coburg, Richmond, Port Melbourne and Prahran. One contact was also among the 20,000-plus crowd gathered for the AFL match between Collingwood and Port Adelaide at the Melbourne Cricket Ground on Sunday.

A nurse conducts a Covid-19 test at a drive-through testing facility at the Melbourne Showgrounds. Photo / Getty Images

So far all positive cases have been connected to each other, although there is still mystery around how the virus was spread from a case in Wollert, on the city's northern fringes, who contracted the virus in hotel quarantine in South Australia.

What's concerning experts is they have all been infected with the more transmissible B. 1.617.2 variant and this may make it difficult to contain the virus without a lockdown.

"This is the more infectious Indian variant so it's spreading quickly, which is what we're seeing," Melbourne University epidemiologist Professor Tony Blakely told news.com.au.

Indian variant making authorities 'nervous'

The state's chief health officer Brett Sutton said the Indian variant spreading in Melbourne was the sub lineage 2 variant, which is as transmissible as the UK strain B.1.1.7.

Blakely said this could be 50 to 100 per cent more infectious than the Wuhan wild-type virus that caused the Melbourne lockdown last year.

While NSW has shown contact tracing can control the wild-type virus, Blakely is worried it not be enough to keep a lid on the new variants.

"This is what we may be seeing playing out in Victoria.

"The fact that we haven't gone into lockdown today shows the chief health officer has more confidence in the contact tracing. I've no reason to dispute that.

Cars line up outside a drive through Covid-19 testing facility at the Melbourne Showgrounds on May 25, 2021. Photo / Getty Images

"But I would be very wary as it is the Indian variant and I know it could go out of control.

"He's nervous and he's said that, I'm also nervous — we're all nervous."

Some restrictions including mask wearing have already been introduced in Victoria but Blakely said without a lockdown it will be crucial for contacts, as well as contacts of contacts, and sometimes even contacts of contacts of contacts, to be isolated urgently.

He said finding, testing and isolating contacts would create "concentric rings of isolation" around the virus that could stop the spread.

"We want to be confident of at least two layers, maybe even three layers are in isolation," he said.

If new cases were only found among the "inner layers" of those contacts (whose contacts had already been put in isolation) this would be a good sign.

"If the system is moving well then maybe we get on top of this," he said.

Melbourne may be headed for another 'ring of steel'

But Blakely is worried about the cases popping up in different circumstances like the workplace in Port Melbourne, where the virus has spread to several colleagues and clients of a positive case.

"We are seeing many cases and lots of contact sites and we haven't tested everyone who has been to these sites so it does look problematic.

"Many contact sites are scattered around Melbourne, not just around the northern suburbs.

"It's hard to believe that we will not have, or need, some form of serious restrictions."

Blakely said given the spread of cases, a zonal lockdown of just the northern suburbs was looking less likely.

"I suspect where we are heading for is another 'ring of steel' with Melbourne restrictions, around stage 3 or 4, travel out to regional Victoria prohibited and possibly around Bendigo itself given there are contact sites there," he said.

Merlino told reporters today that the next 24 hours would be critical to whether more restrictions would be announced.

In order to avoid a lockdown, Blakely said all cases in the next day would need to be contacts who were already in isolation.

If testing also showed no more cases linked to exposure sites then he said he would feel more comfortable about not going into lockdown.

"If the cases only occurred among contacts who were isolated, and their contacts were already in isolation, that might be okay," he said.

But if some tests from exposure sites were coming back positive and authorities were still waiting on tests from other impacted sites, he would be "extremely nervous".