What interventions are needed to stop #COVID19 epidemics?
New paper on this. Wish I had time now to explain in detail why this paper & others are deeply flawed. Hope to do lengthy thread but will need to be very brief here today.
New paper on this. Wish I had time now to explain in detail why this paper & others are deeply flawed. Hope to do lengthy thread but will need to be very brief here today.
Background
Quickly rising case counts led most countries to institute measures to reduce transmission. List of interventions is long. This paper focuses on 5 types: masks, gathering size, business closure, schools/univs, full lockdown.
Quickly rising case counts led most countries to institute measures to reduce transmission. List of interventions is long. This paper focuses on 5 types: masks, gathering size, business closure, schools/univs, full lockdown.
It's hugely important to know how effective each of these interventions are. Some have very limited detrimental effects on economies (limiting gatherings to <100 people) whereas others are devastating (full lockdown).
The problem with this new paper & previous one (nature.com/articles/s4158…) is disentangling effect of one intervention from other interventions &, much more importantly, from other things happening in each country.
This paper tries to use a large sample size of countries with (sometimes) different dates for interventions to estimate individual effects. They do their best & it's a hugely important problem. But I don't think their results are even approximately correct.
Will need much more time to provide full details but for those that want to give it a try digging in on their own here's the fundamental issue:
How do you separate effects of news media reporting rising cases from interventions? How do you separate recommendations from mandates?
How do you separate effects of news media reporting rising cases from interventions? How do you separate recommendations from mandates?
A couple quick examples:
1) CA enacted statewide mask mandate June 12. But mask use started in March & many counties in CA has mask mandates months earlier. No surprise study finds no effect of statewide mask mandates. They aren't indicators of when masks started being used.
1) CA enacted statewide mask mandate June 12. But mask use started in March & many counties in CA has mask mandates months earlier. No surprise study finds no effect of statewide mask mandates. They aren't indicators of when masks started being used.
2) Closures of schools & universities were done at beginning when cases were skyrocketing & public first started realizing there was a pandemic. All the "flatten the curve" messages coincided w/ school/uni closures. Was it the schools/uni closures or incessant global messaging?
Finally, I've been digging deep into local case investigation data. Will have lots to say about that shortly. Quick summary is that ~zero cases are actually linked to businesses or work activities (except HCWs) but closures are powerful signal to change personal behavior.
So much more to write, but suffice to say that temporal analyses of case dynamics/Rt vs timing of interventions are just measuring signaling effects & all ignore key signaling (e.g. media reports). Analyses are at best indirect & at worst misleading.
If you think you can just limit gatherings to <11 & close schools/univs & get reduction in Rt estimated in paper (65% reduction from both; enough to push Rt close to 1) you'll be sorely disappointed while the bodies pile up at hospital & morgue.
There are far better ways to control #COVID19 than using business/school closures to signal the risk of COVID19. I wrote about them here & will update this thread soon with new data that supports case even further:
