Tapiwa Ganyani et al, the one with quantitative estimates of presymptomatic transmission, used data from Singapore up to Feb 26th and Tianjin up to Feb 27th. Both are cities which seem to have achieved containment over the relevant time period. I’m going to focus on Singapore, because information about what Singapore has been doing is easier to come by.
This article has a graph of Singapore’s case counts over the relevant time period, and appears to show it as being contained (R<1) during the relevant time period. This paper estimates the latency between people becoming symptomatic and being isolated in Singapore, and finds that it’s about 3 days for local cases as of Feb 26th, but longer on earlier dates. Their endpoint is “hospitalization or quarantine”, but reading Singapore’s FAQ, it sounds like they have a tiered system with two lesser levels of isolation that the paper doesn’t mention: leave of absence (advice to isolate with no legal force) and stay-home notice (which has legal force against leaving the house, but only a non-binding advisory against having visitors). The lesser isolation tiers are for traced contacts, and would be effective at preventing asymptomatic transmission as well.
My impression from all this is that Singapore’s measures would have driven symptomatic transmission down more than asymptomatic transmission, but substantially driven down both.
Tapiwa Ganyani et al, the one with quantitative estimates of presymptomatic transmission, used data from Singapore up to Feb 26th and Tianjin up to Feb 27th. Both are cities which seem to have achieved containment over the relevant time period. I’m going to focus on Singapore, because information about what Singapore has been doing is easier to come by.
This article has a graph of Singapore’s case counts over the relevant time period, and appears to show it as being contained (R<1) during the relevant time period. This paper estimates the latency between people becoming symptomatic and being isolated in Singapore, and finds that it’s about 3 days for local cases as of Feb 26th, but longer on earlier dates. Their endpoint is “hospitalization or quarantine”, but reading Singapore’s FAQ, it sounds like they have a tiered system with two lesser levels of isolation that the paper doesn’t mention: leave of absence (advice to isolate with no legal force) and stay-home notice (which has legal force against leaving the house, but only a non-binding advisory against having visitors). The lesser isolation tiers are for traced contacts, and would be effective at preventing asymptomatic transmission as well.
My impression from all this is that Singapore’s measures would have driven symptomatic transmission down more than asymptomatic transmission, but substantially driven down both.