Last updated: 2021-01-06-23:03 Melbourne time
Updates daily at 9:15 AM Melbourne time

The road to a COVID-free Victoria

Victoria has emerged from a fairly strict lockdown, that aimed for no local spread of the virus. This was successful - Victoria is now COVID-free and Australia as a whole has very low levels of the virus.

How have Victoria's restrictions affected the spread of the virus? The below plot shows how the effective reproduction number of the virus, Reff has changed over time in Victoria, as well as how the daily cases have changed over time.

How on track was Victoria to meet its targets for easing restrictions in Melbourne? The below plot shows the 14-day average of daily cases, and the targets required to move to each step at their earliest possible dates. The requirement to move to the last step is zero cases for 14 days, which can't be shown on the plot.


The projected trends are simple extrapolations of what will happen if Reff remains at its current value. This does not take into account that things may change. As restrictions are lifted, the virus may have more opportunities to spread and so Reff may increase. On the other hand as case numbers decrease and clusters are better tracked via contact tracing, Reff may decrease. Finally, as case numbers get low, the random chance of how many people each infected person subsequently infects will become more important, and calculating a state-wide average of this (the definition of Reff) will not be particularly meaningful or useful for prediction. As such the projections should be taken with a grain of salt—they are merely an indication of the trend as it is right now.


Source for case numbers: and

Plot/analysis by Chris Billington. Contact: chrisjbillington [at] gmail [dot] com

Python script for producing the plot can be found at