TY - JOUR AU - Leung, Kenneth Siu-Sing AU - Ng, Timothy Ting-Leung AU - Wu, Alan Ka-Lun AU - Yau, Miranda Chong-Yee AU - Lao, Hiu-Yin AU - Choi, Ming-Pan AU - Tam, Kingsley King-Gee AU - Lee, Lam-Kwong AU - Wong, Barry Kin-Chung AU - Man Ho, Alex Yat AU - Yip, Kam-Tong AU - Lung, Kwok-Cheung AU - Liu, Raymond Wai-To AU - Tso, Eugene Yuk-Keung AU - Leung, Wai-Shing AU - Chan, Man-Chun AU - Ng, Yuk-Yung AU - Sin, Kit-Man AU - Fung, Kitty Sau-Chun AU - Chau, Sandy Ka-Yee AU - To, Wing-Kin AU - Que, Tak-Lun AU - Shum, David Ho-Keung AU - Yip, Shea Ping AU - Yam, Wing Cheong AU - Siu, Gilman Kit-Hang T1 - Territorywide Study of Early Coronavirus Disease Outbreak, Hong Kong, China T2 - Emerging Infectious Disease journal PY - 2021 VL - 27 IS - 1 SP - 196 SN - 1080-6059 AB - Initial cases of coronavirus disease in Hong Kong were imported from mainland China. A dramatic increase in case numbers was seen in February 2020. Most case-patients had no recent travel history, suggesting the presence of transmission chains in the local community. We collected demographic, clinical, and epidemiologic data from 50 patients, who accounted for 53.8% of total reported case-patients as of February 28, 2020. We performed whole-genome sequencing to determine phylogenetic relationship and transmission dynamics of severe acute respiratory syndrome coronavirus 2 infections. By using phylogenetic analysis, we attributed the community outbreak to 2 lineages; 1 harbored a common mutation, Orf3a-G251V, and accounted for 88.0% of the cases in our study. The estimated time to the most recent common ancestor of local coronavirus disease outbreak was December 24, 2019, with an evolutionary rate of 3.04 × 10−3 substitutions/site/year. The reproduction number was 1.84, indicating ongoing community spread. KW - novel coronavirus KW - COVID-19 KW - SARS-CoV-2 KW - severe acute respiratory syndrome coronavirus 2 KW - viruses KW - respiratory infections KW - community outbreak KW - whole genome sequencing KW - clinical demographic KW - molecular phylogeny KW - molecular evolutionary analysis KW - Hong Kong KW - China DO - 10.3201/eid2701.201543 UR - https://wwwnc.cdc.gov/eid/article/27/1/20-1543_article ER - End of Reference