Thread by @dbRaevn

🧵VIC - Outbreak progression
#COVID19Vic

It can be easy to treat the current outbreak in VIC as a single cluster, and compare it to how we expect others to progress. A simple chart like this tells a concerning story of growth:

This thread shows why this outbreak is different 🔽

Transmission is driven by "wild" cases - cases found that were out in the community during some or all of their infectious period. So let's take a look at case isolation status over the outbreak.

It looked like it was going well until the 20th August - what happened?

The answer - new clusters were found (MyCenter child care and Shepparton). And just like at the beginning of the outbreak, there was an initial large jump in cases, and new related cases were not isolating. The Wyndham cluster was also later found.

So rather than view this outbreak as a single cluster, it can make more sense if we break it down into the main clusters, as they are fairly independent:

We can now see several things:
- As the new clusters emerge, isolating cases drop significantly initially
- The original cluster is largely reducing
- Only 1 significant cluster appears to be rapidly growing - the Wyndham cluster, which Jeroen raised today as the main concern.

- Other clusters have remained relatively steady, but combined they give the appearance of significant growth.

Note: Unlinked cases will tend to be higher on the most recent days, as they've had the least chance to be linked. This doesn't automatically imply they are growing

Does this mean Victoria has turned a corner? Not quite, and the outcome is still not clear. But there's much more reason to be optimistic when looking into the detail then when just looking at the high level view, and it explains why the progression may not be as expected so far.