The chart below shows clearly the benefits of a lockdown accompanied by extensive testing and tracing (Korea - black line). A delayed and initially less stringent response (to a more widespread outbreak) in Italy is working, but more slowly, as it is beginning to do in Spain.
Delays in responding to the crisis in the USA mean exponential case growth is continuing.
In Australia, lower original transmission has now increased (ie the yellow line has become steeper). Continued prevarication, confusion and delay have likely sown the seeds of a much larger outbreak.
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