Respiratory virus shedding in exhaled breath and efficacy of face masks

Citation: Nancy H. L. Leung, Daniel K. W. Chu, Eunice Y. C. Shiu, Kwok-Hung Chan, James J. McDevitt, Benien J. P. Hau, Hui-Ling Yen, Yuguo Li, Dennis K. M. Ip, J. S. Malik Peiris, Wing-Hong Seto, Gabriel M. Leung, Donald K. Milton, Benjamin J. Cowling (2020) Respiratory virus shedding in exhaled breath and efficacy of face masks.
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Wikidata (metadata): Q89354634
Download: https://www.nature.com/articles/s41591-020-0843-2
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Summary

Screened 3363 from outpatient clinic in Hong Kong, individuals reporting ≥2 ARI symptoms (fever ≥37.8 °C, cough, sore throat, runny nose, headache, myalgia and phlegm), within 3 d of illness onset and ≥11 years of age were eligible to participate, ultimately enrolling 246 participants who were randomized into mask wearing and not mask wearing groups. Infections were confirmed with RT-PCR of (seasonal) coronavirus (n = 17), influenza virus (n = 43), or rhinovirus (n = 54). Participant breaths were collected for 30 minutes.

Found that masks resulted in significant reduced detection of aerosols and droplets for coronavirus, droplets for influenza, and neither for rhinovirus.

Even without a face mask, some participants did not shed detectable virus in respiratory droplets or aerosols: detected rhinovirus in aerosols in 19 of 34 (56%) participants, 4 of 10 (40%) for influenza, and 8 of 23 (35%) for coronavirus, possibly implying that prolonged close contact would be required for transmission to occur or that there is considerable heterogeneity in infectiousness.