• DOI:10.1101/2021.08.13.21261989
• Corpus ID: 236994796

Infectious SARS-CoV-2 in Exhaled Aerosols and Efficacy of Masks During Early Mild Infection

@inproceedings{Adenaiye2021InfectiousSI,
  title={Infectious SARS-CoV-2 in Exhaled Aerosols and Efficacy of Masks During Early Mild Infection},
  author={Oluwasanmi Adenaiye and Jianyu Lai and P. Jacob Bueno de Mesquita and Filbert Hong and Somayeh Youssefi and Jennifer German and Sheldon Tai and Barbara Albert and Maria Telma Gomes Schanz and Stuart M. Weston and Jun Hang and Christian K. Fung and Hye Kyung Chung and Kristen Kelli Coleman and Nicolae Sapoval and Todd J. Treangen and Irina Maljkovic Berry and Kristin E. Mullins and Matthew B. Frieman and Tianzhou Ma and Donald K. Milton},
  booktitle={medRxiv},
  year={2021}
}

• Oluwasanmi Adenaiye, Jianyu Lai, +18 authors D. Milton
• Published in medRxiv 13 August 2021
• Medicine, Biology

Background: SARS-CoV-2 epidemiology implicates airborne transmission; mask source-control efficacy for, variant impact on, and infectiousness of aerosols are not well understood. Methods: We recruited COVID-19 cases to give blood, saliva, mid-turbinate and fomite (phone) swabs, and 30-minute breath samples while vocalizing into a Gesundheit-II, with and without masks at up to two visits two days apart. We quantified and sequenced viral RNA, cultured virus, and assayed sera for anti-spike and anti-receptor binding domain antibodies. Results: We enrolled 61 participants with active infection, May 2020 through April 2021. Among 49 seronegative cases (mean days post onset 3.8 {+/-}2.1), we detected SARS-CoV-2 RNA in 45% of fine ([≥]5 m), 31% of coarse (>5 m) aerosols, and 65% of fomite samples overall and in all samples from four alpha variant cases. Masks reduced viral RNA by 48% (95% confidence interval [CI], 3 to 72%) in fine and by 77% (95% CI, 51 to 89%) in coarse aerosols. The alpha variant was associated with a 43-fold (95% CI, 6.6 to 280-fold) increase in fine aerosol viral RNA that remained a significant 18-fold (95% CI, 3.4 to 92-fold) increase adjusting for viral RNA in saliva, in mid-turbinate swabs, and other potential confounders. Two fine aerosol samples, collected days 2-3 post illness onset, while participants wore masks, were culture-positive. Conclusion: SARS-CoV-2 is evolving toward more efficient airborne transmission and loose-fitting masks provide significant but only modest source control. Therefore, until vaccination rates are very high, continued layered controls and tight-fitting masks and respirators will be necessary.