High attack rate in a Tong Lau house outbreak of COVID-19 with subdivided units in Hong Kong

Qun Wang; David Christopher Lung; Pak-To Chan; Wei Jia; Chung-Hin Dung; Te Miao; Jianxiang Huang; Wenzhao Chen; Zixuan Wang; Kai-Ming Leung; Pengcheng Xu; Zhang Lin; Daniel Wong; Herman Tse; Sally Cheuk Ying Wong; Garnet Kwan-Yue Choi; Kelvin Kai-Wang To; Vincent Chi-Chung Cheng; Kwok-Yung Yuen; Yuguo Li

doi:10.1098/rsfs.2021.0063

High attack rate in a Tong Lau house outbreak of COVID-19 with subdivided units in Hong Kong

Qun Wang, David Christopher Lung, Pak-To Chan, Wei Jia, Chung-Hin Dung, Te Miao, Jianxiang Huang, Wenzhao Chen, Zixuan Wang, Kai-Ming Leung, Pengcheng Xu, Zhang Lin, Daniel Wong, Herman Tse, Sally Cheuk Ying Wong, Garnet Kwan-Yue Choi, Kelvin Kai-Wang To, Vincent Chi-Chung Cheng, Kwok-Yung Yuen, Yuguo Li^*

^*Corresponding author for this work

Research output: Journal Publications and Reviews › RGC 21 - Publication in refereed journal › peer-review

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Abstract

Poor housing conditions are known to be associated with infectious diseases such as high Coronavirus disease 2019 (COVID-19) incidences. Transmission causes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in poor housing conditions can be complex. An understanding of the exact mechanism of transmission can help to pinpoint contributing environmental issues. Here, we investigated a Hong Kong COVID-19 outbreak in early 2021 in four traditional Tong Lau houses with subdivided units. There are more than 80 subdivided units of less than 20 m² floor area each on average. With a total of 34 confirmed COVID-19 cases, the outbreak had an attack rate of 25.4%, being one of the highest attack rates observed in Hong Kong, and ranked among the highest attack rates in reported outbreaks internationally. Tracer gas leakage and decay measurements were performed in the drainage system and in the subdivided units to determine the transport of infectious aerosols by the owner-modified sophisticated wastewater drainage pipe networks and the poor ventilation conditions in some subdivided units. The results show that the outbreak was probably due to multiple transmission routes, i.e. by the drainage pipe spread of stack aerosols, which is enhanced by poor ventilation in the subdivided units.

Original language	English
Article number	20210063
Journal	Interface Focus
Volume	12
Issue number	2
Online published	11 Feb 2022
DOIs	https://doi.org/10.1098/rsfs.2021.0063
Publication status	Published - 6 Apr 2022

Funding

The work was partially supported by the Research Grants Council of Hong Kong’s Collaborative Research Fund (grant no. C7025-16G) and Research Grants Council of Hong Kong’s General Research Fund (grant no. 17203321).

Research Keywords

building ventilation
COVID-19
drainage system
poor housing
SARS-CoV-2

Publisher's Copyright Statement

This full text is made available under CC-BY 4.0. https://creativecommons.org/licenses/by/4.0/

RGC Funding Information

RGC-funded

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1098/rsfs.2021.0063

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Wang, Q., Lung, D. C., Chan, P.-T., Jia, W., Dung, C.-H., Miao, T., Huang, J., Chen, W., Wang, Z., Leung, K.-M., Xu, P., Lin, Z., Wong, D., Tse, H., Ying Wong, S. C., Choi, G. K.-Y., To, K. K.-W., Cheng, V. C.-C., Yuen, K.-Y., & Li, Y. (2022). High attack rate in a Tong Lau house outbreak of COVID-19 with subdivided units in Hong Kong. Interface Focus, 12(2), Article 20210063. https://doi.org/10.1098/rsfs.2021.0063

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title = "High attack rate in a Tong Lau house outbreak of COVID-19 with subdivided units in Hong Kong",

abstract = "Poor housing conditions are known to be associated with infectious diseases such as high Coronavirus disease 2019 (COVID-19) incidences. Transmission causes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in poor housing conditions can be complex. An understanding of the exact mechanism of transmission can help to pinpoint contributing environmental issues. Here, we investigated a Hong Kong COVID-19 outbreak in early 2021 in four traditional Tong Lau houses with subdivided units. There are more than 80 subdivided units of less than 20 m2 floor area each on average. With a total of 34 confirmed COVID-19 cases, the outbreak had an attack rate of 25.4%, being one of the highest attack rates observed in Hong Kong, and ranked among the highest attack rates in reported outbreaks internationally. Tracer gas leakage and decay measurements were performed in the drainage system and in the subdivided units to determine the transport of infectious aerosols by the owner-modified sophisticated wastewater drainage pipe networks and the poor ventilation conditions in some subdivided units. The results show that the outbreak was probably due to multiple transmission routes, i.e. by the drainage pipe spread of stack aerosols, which is enhanced by poor ventilation in the subdivided units.",

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author = "Qun Wang and Lung, {David Christopher} and Pak-To Chan and Wei Jia and Chung-Hin Dung and Te Miao and Jianxiang Huang and Wenzhao Chen and Zixuan Wang and Kai-Ming Leung and Pengcheng Xu and Zhang Lin and Daniel Wong and Herman Tse and {Ying Wong}, {Sally Cheuk} and Choi, {Garnet Kwan-Yue} and To, {Kelvin Kai-Wang} and Cheng, {Vincent Chi-Chung} and Kwok-Yung Yuen and Yuguo Li",

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Wang, Q, Lung, DC, Chan, P-T, Jia, W, Dung, C-H, Miao, T, Huang, J, Chen, W, Wang, Z, Leung, K-M, Xu, P, Lin, Z, Wong, D, Tse, H, Ying Wong, SC, Choi, GK-Y, To, KK-W, Cheng, VC-C, Yuen, K-Y & Li, Y 2022, 'High attack rate in a Tong Lau house outbreak of COVID-19 with subdivided units in Hong Kong', Interface Focus, vol. 12, no. 2, 20210063. https://doi.org/10.1098/rsfs.2021.0063

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T1 - High attack rate in a Tong Lau house outbreak of COVID-19 with subdivided units in Hong Kong

AU - Wang, Qun

AU - Lung, David Christopher

AU - Chan, Pak-To

AU - Jia, Wei

AU - Dung, Chung-Hin

AU - Miao, Te

AU - Huang, Jianxiang

AU - Chen, Wenzhao

AU - Wang, Zixuan

AU - Leung, Kai-Ming

AU - Xu, Pengcheng

AU - Lin, Zhang

AU - Wong, Daniel

AU - Tse, Herman

AU - Ying Wong, Sally Cheuk

AU - Choi, Garnet Kwan-Yue

AU - To, Kelvin Kai-Wang

AU - Cheng, Vincent Chi-Chung

AU - Yuen, Kwok-Yung

AU - Li, Yuguo

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AB - Poor housing conditions are known to be associated with infectious diseases such as high Coronavirus disease 2019 (COVID-19) incidences. Transmission causes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in poor housing conditions can be complex. An understanding of the exact mechanism of transmission can help to pinpoint contributing environmental issues. Here, we investigated a Hong Kong COVID-19 outbreak in early 2021 in four traditional Tong Lau houses with subdivided units. There are more than 80 subdivided units of less than 20 m2 floor area each on average. With a total of 34 confirmed COVID-19 cases, the outbreak had an attack rate of 25.4%, being one of the highest attack rates observed in Hong Kong, and ranked among the highest attack rates in reported outbreaks internationally. Tracer gas leakage and decay measurements were performed in the drainage system and in the subdivided units to determine the transport of infectious aerosols by the owner-modified sophisticated wastewater drainage pipe networks and the poor ventilation conditions in some subdivided units. The results show that the outbreak was probably due to multiple transmission routes, i.e. by the drainage pipe spread of stack aerosols, which is enhanced by poor ventilation in the subdivided units.

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DO - 10.1098/rsfs.2021.0063

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ER -

High attack rate in a Tong Lau house outbreak of COVID-19 with subdivided units in Hong Kong

Abstract

Funding

Research Keywords

Publisher's Copyright Statement

RGC Funding Information

UN SDGs

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