tetano
Editor, Senior Moderator
Interface Focus
. 2022 Feb 11;12(2):20210063.
doi: 10.1098/rsfs.2021.0063. eCollection 2022 Apr 6.
High attack rate in a Tong Lau house outbreak of COVID-19 with subdivided units in Hong Kong
Qun Wang[SUP] 1 [/SUP], David Christopher Lung[SUP] 2 3 [/SUP], Pak-To Chan[SUP] 1 [/SUP], Wei Jia[SUP] 1 [/SUP], Chung-Hin Dung[SUP] 1 [/SUP], Te Miao[SUP] 1 [/SUP], Jianxiang Huang[SUP] 4 [/SUP], Wenzhao Chen[SUP] 1 [/SUP], Zixuan Wang[SUP] 1 [/SUP], Kai-Ming Leung[SUP] 5 [/SUP], Pengcheng Xu[SUP] 6 [/SUP], Zhang Lin[SUP] 7 [/SUP], Daniel Wong[SUP] 8 [/SUP], Herman Tse[SUP] 2 [/SUP], Sally Cheuk Ying Wong[SUP] 2 [/SUP], Garnet Kwan-Yue Choi[SUP] 2 [/SUP], Kelvin Kai-Wang To[SUP] 9 [/SUP], Vincent Chi-Chung Cheng[SUP] 10 [/SUP], Kwok-Yung Yuen[SUP] 9 [/SUP], Yuguo Li[SUP] 1 [/SUP]
Affiliations
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 m[SUP]2[/SUP] 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.
Keywords: COVID-19; SARS-CoV-2; building ventilation; drainage system; poor housing.
. 2022 Feb 11;12(2):20210063.
doi: 10.1098/rsfs.2021.0063. eCollection 2022 Apr 6.
High attack rate in a Tong Lau house outbreak of COVID-19 with subdivided units in Hong Kong
Qun Wang[SUP] 1 [/SUP], David Christopher Lung[SUP] 2 3 [/SUP], Pak-To Chan[SUP] 1 [/SUP], Wei Jia[SUP] 1 [/SUP], Chung-Hin Dung[SUP] 1 [/SUP], Te Miao[SUP] 1 [/SUP], Jianxiang Huang[SUP] 4 [/SUP], Wenzhao Chen[SUP] 1 [/SUP], Zixuan Wang[SUP] 1 [/SUP], Kai-Ming Leung[SUP] 5 [/SUP], Pengcheng Xu[SUP] 6 [/SUP], Zhang Lin[SUP] 7 [/SUP], Daniel Wong[SUP] 8 [/SUP], Herman Tse[SUP] 2 [/SUP], Sally Cheuk Ying Wong[SUP] 2 [/SUP], Garnet Kwan-Yue Choi[SUP] 2 [/SUP], Kelvin Kai-Wang To[SUP] 9 [/SUP], Vincent Chi-Chung Cheng[SUP] 10 [/SUP], Kwok-Yung Yuen[SUP] 9 [/SUP], Yuguo Li[SUP] 1 [/SUP]
Affiliations
- PMID: 35261729
- PMCID: PMC8831081
- DOI: 10.1098/rsfs.2021.0063
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 m[SUP]2[/SUP] 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.
Keywords: COVID-19; SARS-CoV-2; building ventilation; drainage system; poor housing.