How long does it take to bust a COVID cluster?
Welcome kathryn pie. Catherine you've been looking at new south wales datta on the clusters the cluster outbreaks. They've had a new south wales. And you've done some dada crunching. And what have you found. So what i did was. I looked at all the clusters. The new south wales has had since early july when we had the case for melbourne common. Say the crossroads outbreak which really started the new south. Wales second wife. So new south wales health defines a cluster as three people who are epidemiologically linked to what that means is there are three people who've been in physical contact with each other and also that the genome sequencing of the viruses. They have the same. So what i found was a looked eighteen different clusters that we've had in new south wales since july last year and regardless of hammy cases were in the close to what we found is that the cost is lost for about some amount of time. That's three weeks from the first case until the last case is identified so by the end of three weeks you really starting to have found nearly all of the people in that cluster. Now the problem is if they miss anyone that person can then go on and seed a new cluster. So while you got the closure of the crossroads it seeded. Several clusters didn't it. I mean you had the one in the tie restaurant thai rock restaurant and various others and they're all the all kind of trace back to crossroads eventually. So is it true to say that you closed down. After three weeks of the spawned other clusters in some cases they they did. Identify the source in others. Not so like for example. The bankstown area funeral services. The tire crest aren't whether or park by even spy soldiers club. They did not deny the source but they could tell by looking at the genome sequencing that you know it was probably headed had originally come from the crossroads hotel case but they never worked out who that individual was the that crossover between the two clusters so so infecting. What you're seeing. Catherine is well with the system. You got in place in new south wales and presumably. Victoria's well now in other states. The all now work in roughly the same basis you can expect a cluster to be closed at three weeks. But what you don't know is whether you're spawning other clusters which could then get out of control. But if they're if you apply the same methodology then you just keep on going in three week cycles their stride. And that's really what happened in new south wales so they obviously they weren't costas bang bangs sated which soda it just rolled from one to the next but the contact tracers never become overwhelmed by by the cases so they were able to cape h kloster relatively under control and have it shut down after three weeks but they would always be one or two escaped cases that would spawn. The next cost so hard we get to do not days twenty zero for the state. Yeah it's it's tricky. I think what we saw happening last year was even though the epidemiologists say it doesn't matter whether you've got too big or small. Cluster generally lasts about three weeks. The costa's be the custom. Numbers began getting smaller so when we got to october last year we had the oran park. Cluster was twenty three. Papal hawks to the private health clinic was thirteen. And so there's just less. And less people i need to talk to and i guess they can dig a lot. Deeper into those extra cases might be. And in november we got to the end of that last cluster and then we had about a month of new cases bar one which was a transport workout one of controversial things that we were talking about earlier on krona. Cast coverage of the outbreak in northern beaches was when it looked like there was. It was spawning. Other clusters are there were other leaks from overseas was say the issue of whether or not to actually lock down for a short short period of time to just get things under control. Is there any evidence that that speeds up. cluster resolution. Yeah that's that's an interesting one because when you look at these and clusters the only one where we had a lockdown like a. Real lockdown was avalon northern beaches. And yet you didn't say the cluster being shut down any faster than any of the other clusters words. So it's a difficult one to say. It doesn't seem to Circumvent the process by having a really sharp lockdown. Although you know may what what you may do is seedless clusters. So what does the data show about. When sydney's outbreak could end well sharing that they haven't been any new clusters stated that the new south wales health doesn't know about eight. It will repay from the data that we have about another week of of the baramulla cluster to run and then it will come to an end on a data journalist with abc. Thank you very much thank you. So don't we get questions about whether when the virus mutates and we've got these new strains popping up globally with the vaccines that we're getting going to be effective against them and so far we've been saying we've been hearing from experts that yes they will but there was a twitter thread by one of one of the experts in the field in the last couple of days saying that maybe the so-called uk strain the be one one seven variant might not be as effectively targeted by the fis.