SARS-CoV-2 Omicron variant shedding during respiratory activities

Kai Sen Tan; Sean Wei Xiang Ong; Ming Hui Koh; Douglas Jie Wen Tay; Daryl Zheng Hao Aw; Yi Wei Nah; Mohammed Ridzwan Bin Abdullah; Kristen K Coleman; Donald K Milton; Justin Jang Hann Chu; Vincent T K Chow; Paul Anantharajah Tambyah; Kwok Wai Tham

doi:10.1016/j.ijid.2023.03.029

SARS-CoV-2 Omicron variant shedding during respiratory activities

Int J Infect Dis. 2023 Jun:131:19-25. doi: 10.1016/j.ijid.2023.03.029. Epub 2023 Mar 21.

Affiliations

¹ Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore; Infectious Diseases Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore; Biosafety Level 3 Core Facility, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore; Department of Otolaryngology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore.
² National Centre for Infectious Diseases, Singapore; Tan Tock Seng Hospital, Singapore; Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Canada.
³ Department of the Built Environment, College of Design and Engineering, National University of Singapore, Singapore.
⁴ Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore; Infectious Diseases Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore; Biosafety Level 3 Core Facility, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore.
⁵ National Centre for Infectious Diseases, Singapore.
⁶ Institute for Applied Environmental Health, University of Maryland School of Public Health, College Park, Maryland, USA.
⁷ Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore; Infectious Diseases Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore; Biosafety Level 3 Core Facility, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore; Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore.
⁸ Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore; Infectious Diseases Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore.
⁹ Infectious Diseases Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore.
¹⁰ Department of the Built Environment, College of Design and Engineering, National University of Singapore, Singapore. Electronic address: bdgtkw@nus.edu.sg.

Abstract

Objectives: As the world transitions to COVID-19 endemicity, studies focusing on aerosol shedding of highly transmissible SARS-CoV-2 variants of concern (VOCs) are vital for the calibration of infection control measures against VOCs that are likely to circulate seasonally. This follow-up Gesundheit-II aerosol sampling study aims to compare the aerosol shedding patterns of Omicron VOC samples with pre-Omicron variants analyzed in our previous study.

Design: Coarse and fine aerosol samples from 47 patients infected with SARS-CoV-2 were collected during various respiratory activities (passive breathing, talking, and singing) and analyzed using reverse transcription-quantitative polymerase chain reaction and virus culture.

Results: Compared with patients infected with pre-Omicron variants, comparable SARS-CoV-2 RNA copy numbers were detectable in aerosol samples of patients infected with Omicron despite being fully vaccinated. Patients infected with Omicron also showed a slight increase in viral aerosol shedding during breathing activities and were more likely to have persistent aerosol shedding beyond 7 days after disease onset.

Conclusion: This follow-up study reaffirms the aerosol shedding properties of Omicron and should guide continued layering of public health interventions even in highly vaccinated populations.

Keywords: Aerosol transmission; Airborne transmission; COVID-19; Omicron variant of concern; SARS-CoV-2.

MeSH terms

COVID-19*
Follow-Up Studies
Humans
RNA, Viral
SARS-CoV-2

Substances

RNA, Viral

Supplementary concepts

SARS-CoV-2 variants