Viral abundance of SARS-CoV-2 in respiratory aerosols released by COVID-19 patients while breathing, talking, and singing. 

Clinical Infectious Diseases, ciab691, https: //doi.org/10.1093/cid/ciab691

Commentary

This study was designed to determine how airborne SARS-CoV-2 infection occurs and the amount of virus in coarse (>5 μm) and fine (≤5 μm) respiratory aerosols produced during breathing, talking, and singing.

A G-II exhalation collector was used to measure viral RNA in coarse and fine respiratory aerosols emitted by COVID-19 patients during 30 minutes of breathing, 15 minutes of talking, and 15 minutes of singing.

As a result, 13 participants (59%) released detectable levels of SARS-CoV-2 RNA in respiratory aerosols.

The viral load ranged from 63 to 5,821 N gene copies per exhalation activity per participant, with a large variation among people. Patients in the early stages of illness were also more likely to release detectable RNA, with two participants sampled on the third day of illness accounting for 52% of the total viral load.

Overall, 94% of the SARS-CoV-2 RNA copies were released by talking and singing, with seven participants releasing more virus by doing these things.

These fine aerosols constituted 85% of the amount of virus detected in this study, and viral cultures were negative.