Thread by @BooSoonYew67

This is a very good Singapore study that looked into pre-symptomatic transmission in several clusters.. Very comprehensive description !! #COVID19 #SARSCoV2 .. 1/n
cdc.gov/mmwr/volumes/6…

Interesting to note is Cluster B.. where patient B1 was infected at a dinner event on 15 Feb.. had no symptoms.. then transmitted to patient B2 at a singing class on 24 Feb..

Shows a few things here:
1) talking or singing spews out droplets that spreads #COVID19 !! .. 2/n

Patient B1 had 9 days from point of infection on 15/2 till spreading to patient B2 on 24/2.. It's a full 9 days where viral load of #SARSCoV2 will surely be high. High enough in droplets when we talk, or even when we laugh, exclaim etc .. This warrants wearing of masks !! .. 3/n

But problem was if patient B1 then did not feel of any symptoms, then there will be no wearing of mask.. and hence opens risk to Infectivity !!
If any, this finding of pre-symptomatic transmission, some even as early as 2-3 days post infection, shows how masks can prevent. 4/n

Now let's take a look at Cluster A.. a church cluster that had 2 visitors from Wuhan on 19/1 (patients A1 & A2).. but transmitted to 3 others who attended church on same day.
Patient A5 occupied same seat as A1 & A2 shows possible residual #SARSCoV2 on pew/chair .. 5/n

If assuming patient A5 did not have direct meeting with patients A1 & A2, then there is ominous implication of fomite transmission as #SARSCoV2 survives up to 6.8 hours on plastic..
This reinforces need to disinfect surfaces regularly !! .. 6/n
nejm.org/doi/10.1056/NE…

@threadreaderapp unroll

Here's a look at another church cluster.. Patient F1, most likely infected on 27/2 at a singing class.. She probably transmitted to patients F2 & F3 at same church service on 1/3.. Symptoms developed in F2 & F3 on 3/3 & 5/3 consistent with short incubation period; 2-4 days.. 7/n

Again being infected at a singing class, and getting infected during a church service where there is lots of singing hits home the Droplet Transmission.. which sadly hit 1 Church Choir in Skagit County badly.. #COVID19
google.com/amp/s/www.kiro…