Breath-, air- and surface-borne SARS-CoV-2 in hospitals. (February 2021)

• Record Type: Journal Article
• Authors: Zhou, Lian; Yao, Maosheng; Zhang, Xiang; Hu, Bicheng; Li, Xinyue; Chen, Haoxuan; Zhang, Lu; Liu, Yun; Du, Meng; Sun, Bochao; Jiang, Yunyu; Zhou, Kai; Hong, Jie; Yu, Na; Ding, Zhen; Xu, Yan; Hu, Min; Morawska, Lidia; Grinshpun, Sergey A.; Biswas, Pratim; Flagan, Richard C.; Zhu, Baoli; Liu, Wenqing; Zhang, Yuanhang
• Is Part Of: Journal of aerosol science. Volume 152(2021)
• Publication Date: 2021-02
• Subjects: COVID-19 -- SARS-CoV-2 -- Exhaled breath -- Airborne transmission -- Surface-borne; Aerosols -- Periodicals; Aerosols -- Periodicals; Aérosols -- Périodiques; 541.34515
• DOI: 10.1016/j.jaerosci.2020.105693
• Languages: English
• ISSNs: 0021-8502

Abstract

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 (~10 5 RNA copies/m 3 ). 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/cm 2 ). 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/m 3 . 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. Graphical abstract: Image 1 Highlights: Recovering COVID-19 patients (22.2%) still exhale thousands of SARS-CoV-2 per minute. Hospital air (6.8%) was shown to have SARS-CoV-2 levels of 9–219 COVID-19 viruses/m 3 . Surface swabs had a level of 3–8 viruses/cm 2 with a SARS-CoV-2 positive rate of 3.1%.