Breath-, air- and surface-borne SARS-CoV-2 in hospitals

Lian Zhou; Maosheng Yao; Xiang Zhang; Bicheng Hu; Xinyue Li; Haoxuan Chen; Lu Zhang; Yun Liu; Meng Du; Bochao Sun; Yunyu Jiang; Kai Zhou; Jie Hong; Na Yu; Zhen Ding; Yan Xu; Min Hu; Lidia Morawska; Sergey A Grinshpun; Pratim Biswas; Richard C Flagan; Baoli Zhu; Wenqing Liu; Yuanhang Zhang

doi:10.1016/j.jaerosci.2020.105693

Breath-, air- and surface-borne SARS-CoV-2 in hospitals

J Aerosol Sci. 2021 Feb:152:105693. doi: 10.1016/j.jaerosci.2020.105693. Epub 2020 Oct 15.

Authors

Lian Zhou¹, Maosheng Yao², Xiang Zhang³, Bicheng Hu⁴, Xinyue Li², Haoxuan Chen², Lu Zhang², Yun Liu³, Meng Du⁵, Bochao Sun⁶, Yunyu Jiang⁷, Kai Zhou⁸, Jie Hong¹, Na Yu⁹, Zhen Ding¹, Yan Xu¹, Min Hu², Lidia Morawska¹⁰, Sergey A Grinshpun¹¹, Pratim Biswas¹², Richard C Flagan¹³, Baoli Zhu^{1

14}, Wenqing Liu¹⁵, Yuanhang Zhang²

Affiliations

¹ Department of Environment and Health, Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, 210009, China.
² College of Environmental Sciences and Engineering, Peking University, Beijing, 100871, China.
³ The First Affiliated Hospital of Nanjing Medical University (Jiangsu Province Hospital), Nanjing, 210009, China.
⁴ The Clinical Laboratory, Wuhan No.1 Hospital, Wuhan, 430022, China.
⁵ Zhenjiang Center for Disease Control and Prevention, Zhenjiang, 212003, China.
⁶ Yancheng Center for Disease Control and Prevention, Yancheng, 224002, China.
⁷ Taizhou Center for Disease Control and Prevention, Taizhou, 225306, China.
⁸ Suzhou Center for Disease Control and Prevention, Suzhou, 215004, China.
⁹ The First Hospital of China Medical University, Shenyang, 110001, China.
¹⁰ International Laboratory for Air Quality and Heath (ILAQH), WHO Collaborating Centre for Air Quality and Health, School of Earth and Atmospheric Sciences, Queensland University of Technology, Brisbane, Queensland, QLD 4001, Australia.
¹¹ Center for Health-Related Aerosol Studies, Department of Environmental & Public Health Sciences, University of Cincinnati, Cincinnati, OH, 45267, USA.
¹² Department of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, St. Louis, MO, 63130, USA.
¹³ Department of Environmental Science and Engineering and Department of Chemical Engineering, California Institute of Technology, Pasadena, CA, 91109, USA.
¹⁴ Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, 211166, China.
¹⁵ Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei City, Anhui Province, 230031, China.

Abstract

The COVID-19 pandemic has brought an unprecedented crisis to the global health sector. When discharging COVID-19 patients in accordance with throat or nasal swab protocols using RT-PCR, the potential risk of reintroducing the infection source to humans and the environment must be resolved. Here, 14 patients including 10 COVID-19 subjects were recruited; exhaled breath condensate (EBC), air samples and surface swabs were collected and analyzed for SARS-CoV-2 using reverse transcription-polymerase chain reaction (RT-PCR) in four hospitals with applied natural ventilation and disinfection practices in Wuhan. Here we discovered that 22.2% of COVID-19 patients (n = 9), who were ready for hospital discharge based on current guidelines, had SARS-CoV-2 in their exhaled breath (~10⁵ RNA copies/m³). Although fewer surface swabs (3.1%, n = 318) tested positive, medical equipment such as face shield frequently contacted/used by healthcare workers and the work shift floor were contaminated by SARS-CoV-2 (3-8 viruses/cm²). Three of the air samples (n = 44) including those collected using a robot-assisted sampler were detected positive by a digital PCR with a concentration level of 9-219 viruses/m³. RT-PCR diagnosis using throat swab specimens had a failure rate of more than 22% in safely discharging COVID-19 patients who were otherwise still exhaling the SARS-CoV-2 by a rate of estimated ~1400 RNA copies per minute into the air. Direct surface contact might not represent a major transmission route, and lower positive rate of air sample (6.8%) was likely due to natural ventilation (1.6-3.3 m/s) and regular disinfection practices. While there is a critical need for strengthening hospital discharge standards in preventing re-emergence of COVID-19 spread, use of breath sample as a supplement specimen could further guard the hospital discharge to ensure the safety of the public and minimize the pandemic re-emergence risk.

Keywords: Airborne transmission; COVID-19; Exhaled breath; SARS-CoV-2; Surface-borne.