When I tweet about NSW covid, many tweeps assume I'm trolling for political reasons. I'm not. I'm genuinely concerned NSW has undetected spread and should take proactive measures to find it before it explodes. To explain why I'm anxious, let's look at Victoria. A thread

We now know Victoria had a crisis brewing in June. 2nd wave started end of May when covid got out of hotel quarantine. Even though daily cases were low, there was unknown transmission evident from pretty much the beginning of June. This was evidence of undetected spread.

People need to remember the cases picked up in testing are not necessarily the number of actual cases there are out there. Victoria had many more cases, possibly hundreds, in June which they didn't pick up through routine testing. Every unknown case is a potential crisis.

So, when did Victoria realise they had a major problem? It terrifies me how quickly things blew up in Victoria after covid got out of hotel quarantine end of May. Victoria was still partly locked down first two weeks of June - restaurants and cafes were only doing take away.

Cases were trickling along in first three weeks of June - first half of the month single figure rises each day, second half into the tens and then twenties. By 22 June, these were Victoria's case numbers:
16 new cases
4 international HQ
6 local known contacts
6 local unknown

We know now that those case numbers were only the tip of the iceberg compared to the real number of cases out there. Victorian govt must have suspected this too, as on June 23, they changed restrictions to only allow a maximum of 5 people in a home.

Two days later, the problem was clearly escalating (although numbers weren't blowing out yet). On June 25, Vic had 25 cases and announced they were going into ten hot spot suburbs to try to find undetected spread. They went door to door testing everyone who agreed to be tested.

Clearly as a result of this testing blitz, they decided to lock just those suburbs down on June 30 (76 cases that day). I think it's important to look back and note Victoria didn't get to these high figures until they went looking for cases. There was serious undetected spread.

On July 4, cases were identified in public housing towers. This was the day towers were locked down and it was discovered after testing every resident that one tower in particular was badly hit by undetected spread - over 170 cases were found after testing every single resident.

Once Victoria discovered just how much undetected spread they had they locked down. From 6 unknown cases June 22 to July 10, they grew to 281 new cases and 262 under investigation (possible unknown source). July 7 was start of stage 3 lockdown, and cases exploded. Aug 2, stage 4.

A lot has been said about contact tracing. But once unknown cases start to be detected - like they were in Victoria once they realised just how much spread there had been, there's not much contract tracers can do at that point. Unknown source is by definition, not traceable.

When I look at what has happened in Victoria, I just think about things they could have done differently over those four weeks from end of May to end of June when undetected spread got out of control. That's why I wish NSW would learn from Victoria and try to avoid same happening

I'm sure contact tracing could have been better. As I've said over and over, contact tracing is just one tool, and once unknown cases explode (invisibly) there is not much contact tracers can helpfully do to contain spread. It's already out there - unconstrained and unknown.

I believe the most important factor which contributed to the large growth in undetected spread in Victoria, apart from bad luck (a super spreader getting away from contact tracers) and just how contagious second wave covid is, is that people didn't want to miss work to get tested

Victoria played catch up on dealing with this problem by bringing in payments for people to stay home and get tested, and paid pandemic leave to make sure those who had covid did stay home rather than taking it into workplaces.

If Victoria had time over, in hindsight, these policies were needed well before second wave hit. In my opinion, there is no way to safely live alongside covid because undetected spread is always a risk. But if you are forced to, at least incentivise people to get tested. End.