A reason for hope in NSW

On Saturday 31 July, South East Queensland went into lockdown in response to the Indooroopilly outbreak. Being dutiful citizens of Brisbane’s inner western suburbs, we checked the contact tracing locations and spent Sunday getting tested; after a few days I noticed that the new contact tracing sites pretty much stopped on the Saturday afternoon, aside from a few exceptions (see graph below).

It’s pretty obvious, we are all out and about doing our thing in the community, up until Saturday morning, then we went home and started isolation and therefore new close contact sites (and hopefully new transmissions) pretty much stop from that point forward.

So what about NSW, where the situation is more serious and an extended lockdown has been in place? Here’s the data over a similar period.

Well I’m pleased to say that the data indicates that the number of new close contact sites in NSW is trending downwards.

These data seemingly conflict with case numbers rising day by day in NSW; however, we know that the incubation period of COVID is in the order of weeks, so case numbers reported today, reflect behaviour in the community that occurred 1-2 weeks ago. So, if close contact sites is a proxy for probability of transmission on any given day, we should start to see the new community case numbers start to pull back over the next week.

Although case numbers are rising, there is a good indication to support the argument that current efforts by the community and our contact tracers in Queensland and NSW are effective and will lead to a corresponding decline in case numbers, if we continue to do the right thing.

Of course if contact tracing is compromised (not checking in, not reporting accurately, ineffective/insufficient contact tracing), then the indication is less accurate.

Wear a mask, get vaccinated, get tested, stay home.

As a general caveat, I had to do a lot of manual data cleaning to produce the above drafts, there are probably some errors, so please forgive me if this is the case.