Australia is only a few days into its latest regime of strict self-isolation measures designed to fight the coronavirus pandemic, but already, many people are asking — when will they end?

Not before late July at the very earliest, modelling from the University of Sydney suggests.

The model, first published last week and now updated, shows:

Strict physical-distancing measures are beginning to work and Australians appear to have been about 90 per cent compliant with advice to stay at home wherever possible

Strict physical-distancing measures are and Australians appear to have been about 90 per cent compliant with advice to stay at home wherever possible However, scaling back our isolation regime would cause case numbers to spike dramatically — until such time as new measures, especially more testing, are in place

However, — until such time as new measures, especially more testing, are in place With the current measures, Australia should be close to the peak of new infections

Modelling suggests isolation measures are having an impact, but removing them will need to be carefully handled. ( ABC News: Ben Spraggon )

This kind of modelling is designed to help understand how different actions will affect the spread of COVID-19 through the community.

It doesn't make specific predictions of what will happen in the real world, but is an important tool governments are using to decide what actions to take to save lives.

Prime Minister Scott Morrison has said Australia's coronavirus pandemic measures will be in place for at least six months and "it could be longer".

This modelling helps explain why.

First, the good news…

The chart above shows how Australia's coronavirus outbreak might respond under three different scenarios. Here's how they work:

In each case, physical-distancing measures are kept in place for three months — along with border controls and quarantine restrictions for those with COVID-19

In each case, physical-distancing measures are kept in place for three months — along with border controls and quarantine restrictions for those with COVID-19 If only 70 per cent of the population is compliant with the isolation measures, cases keep rising almost unchecked

If only 70 per cent of the population is compliant with the isolation measures, cases keep rising almost unchecked The best scenario is when there is 90 per cent compliance with physical distancing, which brings the case numbers down close to zero

Mikhail Prokopenko, who led the University of Sydney research, has compared his model to what's happening in the real world — and has some good news.

It indicates that Australians have been about 90 per cent compliant with physical-distancing measures.

"The agreement between the simulated and actual number of cases in Australia most closely matches the 90 per cent compliance with physical distancing scenario," Professor Prokopenko says.

"In the days before March 24, the physical distancing was weaker than it is now."

According to the model, if we maintain 90 per cent compliance, the peak in the number of new coronavirus cases should occur around now. The real-world data appears to show a similar pattern at the moment.

But it's still very early days…

The tail end of the chart shows what could happen if physical-distancing measures are lifted too soon, or too quickly.

The result could be a rapid, potentially disastrous, exponential rise in cases — even if there has previously been 90 per cent compliance.

This provides an indication of why officials are preparing Australians for at least three months of huge changes to their usual lives.

If cases are just going to spike again, what is the point of physical distancing?

Professor Prokopenko is hopeful that a rebound is not a foregone conclusion.

"If we have better and more efficient testing, and good contact tracing of cases, we can track down all remaining cases and reduce them to zero," he says.

"Even asymptomatic people could be tested to catch all the cases immediately."

He expects that testing time could be reduced to two to three days by the time a three-month lockdown scenario ends — and will be far more widespread than it is now.

That aligns with an outlook Dr Norman Swan, host of the ABC's Coronacast, has set out if the community maintains strict social-isolation measures.

"If we all get behind this, we stay at home, we minimise our mixing with other people, kids stay at home and we do it tough for a period of time, you could get it down to really low levels," he says.

However, he confirms Australia's testing regime will have to change dramatically.

"The testing regime has to move towards, at a minimum, everyone with symptoms — and finding a way to get to asymptomatic people too. "Essentially there has to be a very big, extensive testing program put into place over the next few weeks around Australia."

Australia has already ordered 1.5 million tests to detect who has been infected with coronavirus.

Isolation measures will remain crucial even when case numbers drop

Professor Prokopenko says that even if the number of cases in Australia slows to a trickle, and a new testing regime is in place, an additional month of physical-distancing restrictions will be needed to ensure all the cases have been tracked down.

"One person can transfer the virus to one other person for up to 17 days, and for another 17 days that person can also transfer the virus to others," he says.

"People will complain about maintaining social distancing when there are no cases, but it is necessary to stop the spread."

So, all up, that would likely point towards four months of strict social distancing, taking us up to late July.

Dr Swan says that as well as more testing, physical distancing must also be combined with strict quarantines for anyone who has COVID-19 until they are "truly negative".

"That sort of regime, where you've got quarantine, isolation and extended testing, if you get [new cases] down to very low levels, and at that point when you've got the systems in place, that's where you might say, let's just take the foot off the pedal a little bit" in terms of the isolation measures, he says.

"We won't get back to normal, by the way, until there's a vaccine," Dr Swan says. "But we get to the point where it's manageable."

"It'll be a long, long time before we allow international flights … but if we can get back to people starting going to work, kids going to school … you just do one thing at a time, steadily, and see what happens."

Dr Swan says a steady approach will be critical to avoid a second or third wave of infections, which could be even worse than the first wave.

How does the coronavirus model work?

The University of Sydney researchers have built what is effectively a simulation of the entire Australian population using information about where everyone lives, the number of adults and children in each house, how people move around their town or city, and other details such as the locations of schools and airports.

They then essentially add COVID-19 into that simulation, watch how it spreads — and can experiment with how different measures might change its growth.

The modelling was created by the Centre for Complex Systems and the Marie Bashir Institute for Infectious Diseases and Biosecurity at Sydney University.

It has been published online but has not yet been through a rigorous peer-review process.

In this model, physical distancing is defined as people staying at home, having no contact with their work colleagues and 50 per cent less contact with the rest of the world, apart from their own household.

Under this simulation, strict social distancing begins on March 24, the day Prime Minister Scott Morrison asked Australians to stay at home and not congregate in groups.

It is also the day Australia recorded 2,000 cases. The physical-distancing measures are kept in place for three months.

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Are governments using this modelling?

Professor Prokopenko's modelling is for academic purposes, and to help inform the public. Australian governments are using their own modelling to help guide the coronavirus response.

The Australian Academy of Science has been calling for the Federal Government to release that modelling to the public, and Prime Minister Scott Morrison has now said authorities plan to release information about the models next week.

Both New Zealand and the UK have released information about their modelling to the public.

What should I do to help?

The National Cabinet says all Australians should stay home unless they are:

Shopping for "food and necessary supplies"

Shopping for "food and necessary supplies" Providing medical, healthcare or compassionate services (i.e. taking on the role of a carer)

Providing medical, healthcare or compassionate services (i.e. taking on the role of a carer) Exercising in a group of two or less (or exclusively with members of their household)

Exercising in a group of two or less (or exclusively with members of their household) Working or studying if they cannot do so remotely

Scott Morrison announced on Sunday that indoor and outdoor gatherings could not be bigger than two people, with the exception of:

People of the same household gathering together

People of the same household gathering together Funerals, where a maximum of 10 people can gather

Funerals, where a maximum of 10 people can gather Weddings, where there can be up to five people

Weddings, where there can be up to five people Family units, which is understood to mean immediate family

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