Victorian lockdown worked: it stopped community transmission of Covid

Science before politics

Some are claiming the Victorian lockdown was too late, saying the rate of spread was already suppressed before it started. But that misses the point that slowing flight arrivals was responsible for most of the suppression up to that point, but that wasn’t going to stop the rising cases of community transmission. To judge if lockdown works, we need to look at domestic spread.

The graph that matters are the new daily cases, and even more so, the graph of daily new cases due to of community transmission (below).

Victoria started a major lockdown on March 24th when schools were largely closed (except to essential workers) and only essential services were allowed to run. We see daily new cases peaked 11 days later, almost exactly as expected (with the same delay as Japan, Germany, Italy, Spain, South Korea and Norway). The 12 day average expected lag comes from a five day average incubation and then a roughly seven day lag for new cases to get into breathing trouble and get tested as such.

Victoria, All Daily New Cases | Source: Covid19data

Most of the early spread was from foreign arrivals

Lockdown is aimed to slow community […]