TY - JOUR
T1 - Spread of SARS-CoV-2 aerosols via two connected drainage stacks in a high-rise housing outbreak of COVID-19
AU - Wang, Qun
AU - Lin, Zhang
AU - Niu, Jianlei
AU - Choi, Garnet Kwan Yue
AU - Fung, Jimmy C.H.
AU - Lau, Alexis K.H.
AU - Louie, Peter
AU - Leung, Kenneth K.M.
AU - Huang, Jianxiang
AU - Cheng, Pan
AU - Zhao, Pengcheng
AU - Chen, Wenzhao
AU - Zhang, Sheng
AU - Fu, Liye
AU - Chan, P. W.
AU - Wong, Ann Han
AU - Tse, Herman
AU - Wong, Sally Cheuk Ying
AU - Lai, Raymond Wai Man
AU - Hui, David SC
AU - Yuen, Kwok Yung
AU - Lung, David Christopher
AU - Li, Yuguo
N1 - Funding Information:
We thank Pak-To Jack Chan, Shenglan Xiao, Nan Zhang, and Maosu Li of the University of Hong Kong; Jian Liu, Yanlin Lu, and Yafeng Gao of the City University of Hong Kong; Kit Hung and Michael Fung of The Hong Kong Polytechnic University; and Kwong Hoi Tsui, Ka Wing Shek, Ngai Ting Lau, Kwok Pong Ho, Weiwei Chan, Billy Wong, and Hao Liu of the Hong Kong University of Science and Technology for participating in the field measurements. We thank Professor Wilson Lu, Dr Fan Xue, Dr Ruoyu You, Dr Charles Wong, and Dr Chao Ren for their support and Dr Vincent Cheung for coordinating the field measurements. We are also grateful to many individuals at CHP, EPD, and the Housing Department for their coordination and support during the course of this research. This study was partially supported by the Research Grants Council of Hong Kong with a Collaborative Research Fund (grant number C7025-16G) and a General Research Fund (grant number 17203321) grant.
Funding Information:
We thank Pak-To Jack Chan, Shenglan Xiao, Nan Zhang, and Maosu Li of the University of Hong Kong; Jian Liu, Yanlin Lu, and Yafeng Gao of the City University of Hong Kong; Kit Hung and Michael Fung of The Hong Kong Polytechnic University; and Kwong Hoi Tsui, Ka Wing Shek, Ngai Ting Lau, Kwok Pong Ho, Weiwei Chan, Billy Wong, and Hao Liu of the Hong Kong University of Science and Technology for participating in the field measurements. We thank Professor Wilson Lu, Dr Fan Xue, Dr Ruoyu You, Dr Charles Wong, and Dr Chao Ren for their support and Dr Vincent Cheung for coordinating the field measurements. We are also grateful to many individuals at CHP, EPD, and the Housing Department for their coordination and support during the course of this research. This study was partially supported by the Research Grants Council of Hong Kong with a Collaborative Research Fund (grant number C7025-16G ) and a General Research Fund (grant number 17203321 ) grant.
Publisher Copyright:
© 2022 Elsevier B.V.
PY - 2022/5/15
Y1 - 2022/5/15
N2 - Vertical transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) along a vertical column of flats has been documented in several outbreaks of coronavirus disease 2019 (COVID-19) in Guangdong and Hong Kong. We describe an outbreak in Luk Chuen House, involving two vertical columns of flats associated with an unusually connected two-stack drainage system, in which nine individuals from seven households were infected. The index case resided in Flat 812 (8th floor, Unit 12), two flats (813, 817) on its opposite side reported one case each (i.e., a horizontal sub-cluster). All other flats with infected residents were vertically associated, forming a vertical sub-cluster. We injected tracer gas (SF6) into drainage stacks via toilet or balcony of Flat 812, monitored gas concentrations in roof vent, toilet, façade, and living room in four of the seven flats with infected residents and four flats with no infected residents. The measured gas concentration distributions agreed with the observed distribution of affected flats. Aerosols leaking into drainage stacks may generate the vertical sub-cluster, whereas airflow across the corridor probably caused the horizontal sub-cluster. Sequencing and phylogenetic analyses also revealed a common point-source. The findings provided additional evidence of probable roles of drainage systems in SARS-CoV-2 transmission.
AB - Vertical transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) along a vertical column of flats has been documented in several outbreaks of coronavirus disease 2019 (COVID-19) in Guangdong and Hong Kong. We describe an outbreak in Luk Chuen House, involving two vertical columns of flats associated with an unusually connected two-stack drainage system, in which nine individuals from seven households were infected. The index case resided in Flat 812 (8th floor, Unit 12), two flats (813, 817) on its opposite side reported one case each (i.e., a horizontal sub-cluster). All other flats with infected residents were vertically associated, forming a vertical sub-cluster. We injected tracer gas (SF6) into drainage stacks via toilet or balcony of Flat 812, monitored gas concentrations in roof vent, toilet, façade, and living room in four of the seven flats with infected residents and four flats with no infected residents. The measured gas concentration distributions agreed with the observed distribution of affected flats. Aerosols leaking into drainage stacks may generate the vertical sub-cluster, whereas airflow across the corridor probably caused the horizontal sub-cluster. Sequencing and phylogenetic analyses also revealed a common point-source. The findings provided additional evidence of probable roles of drainage systems in SARS-CoV-2 transmission.
KW - Airflow
KW - COVID-19
KW - Drainage system
KW - SARS-CoV-2
KW - Stack aerosol
UR - http://www.scopus.com/inward/record.url?scp=85125861946&partnerID=8YFLogxK
U2 - 10.1016/j.jhazmat.2022.128475
DO - 10.1016/j.jhazmat.2022.128475
M3 - Journal article
C2 - 35183827
AN - SCOPUS:85125861946
SN - 0304-3894
VL - 430
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
M1 - 128475
ER -