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Coronavirus disease (COVID-19) outbreak during Chinese New Year dinner in a restaurant, Hong Kong (China), 2020
Letter to the Editor
Tsz-sum Lam, Chi-hong Wong, Wing-hang Lam, Ho-yeung Lam, Yonnie Chau-kuen Lam, Emily Chi-mei Leung and Shuk-kwan Chuang
Communicable Disease Branch, Centre for Health Protection, Department of Health, Hong Kong, People’s Republic of China.
Correspondence to Tsz-sum Lam (e-mail: [email protected]).
The current pandemic of coronavirus disease (COVID-19) was first reported from Wuhan, China on 31 December 2019.
1 The first imported confirmed case from Wuhan to Hong Kong was recorded on 23 January 2020. 2 COVID-19 outbreak was declared as Public Health Emergency of International Concern on 30 January 2020 by the World Health Organization (WHO). 3 We reported a local family cluster of 6 confirmed COVID-19 cases, among 29 attendees of a Chinese New Year family dinner gathering in a restaurant on 26 January 2020 which was the second day of Chinese New Year.
On 10 February 2020, we received notification of a confirmed case of COVID-19 involving a 37-year-old female (patient 1) who had developed fever, cough and sore throat since 2 February 2020. She was admitted to a public hospital on 10 February 2020 and her nasopharyngeal aspirate was tested positive for SARS-CoV-2.
Contact tracing revealed that her husband who resided with her developed fever and cough on 30 January 2020 (patient 2). Moreover, her father who did not reside with her developed fever and cough since 3 February (patient 3). They were admitted for isolation and tested positive for SARS-CoV-2.
The 3 patients shared the Chinese New Year dinner with 26 other relatives on 26 January 2020. Three more relatives were found to be symptomatic from 31 January to 8 February 2020 and tested positive for SARS-CoV-2 (patients 4 to 6).
The 29 attendees lived in separate residences and the family dinner was the only common exposure among all 6 confirmed cases during the incubation period. It was held in a restaurant with mahjong-playing lasted for around 7 hours. No game meat was consumed. None of the attendees were symptomatic during the gathering. There was data suggesting that some people can be tested positive for COVID-19 from 1-3 days before they develop symptoms. 4
Contact tracing identified 1 domestic helper who did not join the family dinner but shared bedroom in the same household with patient 4 (symptom onset on 31 January) developed fever and cough since 2 February and was tested positive for SARS-CoV-2 (patient 7, figure 1). In summary, the cluster of 6 + 1 confirmed cases consisted of 3 males and 4 females aged 32 to 75 (median: 37). All of them had no travel history outside Hong Kong during the incubation period and discharged home uneventfully.
2
WHO advised maintain social distancing of at least 1 metre (3 feet) as basic protective measures against the COVID-19.
5 Mahjong is commonly played by 4 players sitting around a square table in close proximity for hours, player-player distance is usually less than 1 metre which allows respiratory droplet transmission. Chinese dinner is commonly shared by 12 diners sitting at a round table in proximity. 29 diners squeezed into 2 tables usually accommodating 24 persons further reduced social distancing.
Our findings supported effective human-to-human transmission of COVID-19 through social activities and appeals the public to properly maintain social distancing at all times during the COVID-19 pandemic.
Figure 1. Epidemic Curve
References:
1. WHO Novel Coronavirus (2019-nCoV) Situation Report -1. Available from: https://www.who.int/docs/default- source/coronaviruse/situation-reports/20200121-sitrep-1-2019-ncov.pdf?sfvrsn=20a99c10_4 [accessed 17 April 2020].
2. Latest situation of cases of COVID-19 in Hong Kong. Available from:
https://www.chp.gov.hk/files/pdf/local_situation_covid19_en.pdf [accessed 17 April 2020].
3. WHO Statement on the second meeting of the International Health Regulations (2005) Emergency Committee regarding the outbreak of novel coronavirus (2019-nCoV). Available from: https://www.who.int/news- room/detail/30-01-2020-statement-on-the-second-meeting-of-the-international-health-regulations-(2005)- emergency-committee-regarding-the-outbreak-of-novel-coronavirus-(2019-ncov) [accessed 17 April 2020].
4. WHO Coronavirus disease 2019 (COVID-2019) Situation Report -73. Available from:
https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200402-sitrep-73-covid- 19.pdf?sfvrsn=5ae25bc7_2 [accessed 17 April 2020].
5. WHO Coronavirus disease (COVID-19) advice for the public. Available from:
https://www.who.int/emergencies/diseases/novel-coronavirus-2019/advice-for-public [accessed 17 April 2020].
5 4 3 2 1
16 Jan 2020 25 Jan 2020 26 Jan 2020 27 Jan 2020 28 Jan 2020 29 Jan 2020 30 Jan 2020 31 Jan 2020 1 Feb 2020 2 Feb 2020 3 Feb 2020 4 Feb 2020 5 Feb 2020 6 Feb 2020 7 Feb 2020 8 Feb 2020 9 Feb 2020 10 Feb 2020 11 Feb 2020 12 Feb 2020 13 Feb 2020 14 Feb 2020 15 Feb 2020 16 Feb 2020 17 Feb 2020 18 Feb 2020 19 Feb 2020 20 Feb 2020 21 Feb 2020 22 Feb 2020
: primary case : secondary case family dinner
Onset date
Number of cases
