A superspreading event involving a cluster of 14 coronavirus disease 2019 (COVID-19) infections from a family gathering in Hong Kong SAR (China)

• Main Authors: Ho Yeung Lam, Tsz Sum Lam, Chi Hong Wong, Wing Hang Lam, Chi Mei Emily Leung, Chau Kuen Yonnie Lam, Tin Wai Winnie Lau, Chi Hin Billy Ho, Ka Hing Wong, Shuk Kwan Chuang
• Format: Article
• Language: English
• Published: World Health Organization Regional Office for the Western Pacific 2020-12-01
• Series: Western Pacific Surveillance and Response
• Subjects: coronavirus disease 2019; sar-cov-2; virus; outbreak; social distancing; hong kong; novel coronavirus
• Online Access: https://ojs.wpro.who.int/ojs/index.php/wpsar/article/view/722
• ISSN: 2094-7321; 2094-7313

Objectives: An outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in Wuhan, China in December 2019, with subsequent spread around the world. Hong Kong, a Special Administrative Region of China, recorded its first confirmed case on 23 January 2020. In this report, we describe a family cluster of 12 confirmed cases with 2 additional confirmed cases from secondary transmission. Method: We reported the epidemiological, clinical and laboratory findings of the family cluster and the public health measures instituted. Results: All 12 confirmed COVID-19 cases were among the 19 attendees of a 3-hour Chinese New Year family dinner consisting of hotpot and barbecue. Environmental sampling of the gathering venue was negative. 2 additional confirmed cases who were the co-workers of 2 confirmed cases were later identified, indicating secondary transmission. Contact tracing, quarantine and environmental disinfection were instituted to contain further spread. Discussion: Our findings are highly suggestive of a superspreading event during the family gathering. The source is likely one of the cases during the asymptomatic phase. It attested to the high infectivity of SARS-CoV-2 through human-to-human transmission from social activities and argued for the necessity of social distancing in curtailing the disease spread.