The closure of the Vic - NSW border is welcome. So is the Victorian judicial inquiry into the security of the isolation process. Looking at the successive lows in the recent graphs of new cases in Australia, if appears that the daily new cases needs to be under 100 to signal control of the Victorian 'cluster'.
After the 1 May, when restrictions were eased, the effective estimated R0 was 0.94 which is very close to the epidemic R0 of 1 or more. So only a slight error in process or policing or compliance would result in a large cluster or second wave. And it did. It would appear that the only effective way to deal with a cluster or second wave is to act fast and effectively - the 'hit it hard and fast and early' policy. The critics will claim that time and money was wasted because nothing happened. But that is the point. In preventive medicine the biggest success is when nothing happens. When the R8 is 1 or more then something is definitely happening. And it needs to be Hit Hard and Hurriedly.
R8 is the estimated recent apparent R0 calculated from the cases over the preceding 8 days.
The chart below also suggests that the New Cases would need to be below 100 to be lower than the trend of the recent 'lowest lows', and signal a new downward trend. It could be tomorrow.