11-02-2020, 09:55 AM
Here's what Vietnam did:
[tweet]https://twitter.com/Birdyword/status/1323088509855412224?s=20[/tweet]
The insight here is that it catches asymptomatic transmission and would cover transmission delays and to a degree sub-optimal tracking. There's a decent chance that if your F0 didn't identify all contacts, the F1 (contact of a positive test) could identify some mutual contacts with the F0, which would still be isolated. Moreover, if there was a delay in detecting the F0 case, you already have all the F1 contacts (the F2s) just in case one of the F1's subsequently turns positive. But wait, they go all the way to F5's with measures commensurate with risk, so that while all F0's go to the hospital, and all F1's are centrally quarantined, the F4's and F5's are merely advised to isolate at home. Given the patterns of asymptomatic transmission, this likely broke some chains of transmission that would have otherwise gone undetected.
I think the challenge is that I bet in Vietnam they had a pretty good compliance with tracking measures, whereas we know that when it has been tried in the US, the median F0 identifies only one contact.
BC
[tweet]https://twitter.com/Birdyword/status/1323088509855412224?s=20[/tweet]
The insight here is that it catches asymptomatic transmission and would cover transmission delays and to a degree sub-optimal tracking. There's a decent chance that if your F0 didn't identify all contacts, the F1 (contact of a positive test) could identify some mutual contacts with the F0, which would still be isolated. Moreover, if there was a delay in detecting the F0 case, you already have all the F1 contacts (the F2s) just in case one of the F1's subsequently turns positive. But wait, they go all the way to F5's with measures commensurate with risk, so that while all F0's go to the hospital, and all F1's are centrally quarantined, the F4's and F5's are merely advised to isolate at home. Given the patterns of asymptomatic transmission, this likely broke some chains of transmission that would have otherwise gone undetected.
I think the challenge is that I bet in Vietnam they had a pretty good compliance with tracking measures, whereas we know that when it has been tried in the US, the median F0 identifies only one contact.
BC