It is possible for the western half of Australia to begin to relax COVID-19 restraints earlier than states in the east but the surveillance system required to keep them safe is not yet in place, according to one of the government’s chief modellers.

Sydney has a bigger problem than the rest of NSW, just as the north west of Tasmania has a bigger problem than the rest of the state. Tasmania has the highest rate of infection per 100,000, at 38.3, and the highest rate of deaths per 100,000, at 1.5. NSW has 36.7 cases per 100,000 and 0.4 deaths per 100,000.
On Thursday, the total number of cases crept up by just eight to 6659 at 5.30pm AEST, with no new cases in WA and SA. Two new deaths brought the toll to 76.
Although some states have relatively small numbers of cases at the moment, they have areas that are particularly vulnerable,” Dr Snow said.
WA, the Northern Territory and parts of Queensland have many vulnerable regional and remote communities where even 20 cases could be a complete disaster, she said.
In Cairns, six health workers were knocked out of circulation by just one case, reducing the city’s ability to manage an outbreak.
Although the Reff (the number of new cases produced by one case at the present time) is below one in all states, this is no guarantee it will keep going down, she said.
There is a huge element of luck. There is a significant random element. Its a bit like a bushfire. It can change direction and get bigger and smaller very quickly,” Dr Snow said.
Even with restrictions we now have, we could see a large outbreak, as in Tasmania. There are lot of risks and networks of people that we cant break up and mitigate.
If COVID-19 got into a prison that will change very rapidly. Many people go in and out of prisons every day and could take the virus with them. Its luck that so far, they have not.
All states have potential high-risk, high-density areas, like aged homes and prisons, where people are confined. Some have immigration detention centres, too.
These present structural problems for controlling infection, where a spot fire can become large fire front.
Dr Snow has cautionary words for people who think because their state has not had a case for days, it is time to relax.
Everything is still very fragile, everyone is still vulnerable, especially in regional and remote centres where the situations can change very, very quickly.
Professor McCaw and Dr Snow were talking at a Q&A session for the press run by the Australian Science Media Centre.