Thread by @seanongwx

1/ Our paper is now published in final peer-reviewed form in CID! In this study, we recruited 22 #COVID19 patients at NCID and collected breath samples using a G-II machine while they were talking, breathing, and singing.
@IDSAInfo @drkristenkc @Don_Milton
doi.org/10.1093/cid/ci…

2/ 13 (59%) of patients had detectable #SARSCoV2 RNA by PCR in exhaled breath samples, with 85% comprising fine aerosols <5um. There was significant variation between patients, with 2 patients accounting for 52% of the total viral load - may explain so-called "super-emitters".

3/ Detectable RNA in aerosol was associated with earlier day of illness: median 3d (IQR 2-5) for those with detectable RNA vs 5d (4-7) for those without. It is clear that patients are most infectious at illness onset, emphasising need for early case detection and isolation.

4/ Singing was associated with the greatest "viral load", compared to talking and breathing. Coupled with epidemiologic evidence of numerous outbreaks associated with singing, it is clear that this is a high-risk activity that we should be vigilant during re-opening.

5/ Of note, all viral cultures were negative - though this should be taken with a pinch of salt as there are numerous methodological limitations to viral culture, as we expound upon in the Discussion. Absence of evidence is not evidence of absence!

6/ Taken altogether, our data contributes to the further understanding of #aerosol transmission as a significant route of #COVID19 transmission. Multi-layered interventions to control this and improve indoor air quality are important as we learn how to live with endemic COVID.

(Check out the photo of this crazy machine, as demonstrated by Douglas!)