With Australia’s borders effectively locked and a diminishing number of returning citizens quarantined for two weeks, the key to the nation’s physical and economic health will be the level of future infection from no identifiable source.

This is now nearly 10 per cent of COVID-19 cases and Chief Medical Officer Brendan Murphy says it’s the number that concerns him most. That is despite the obvious relief the daily increase in overall numbers is consistently reducing – ahead of the release of official modelling figures on Tuesday.