Analysis on infection sources and transmission chains of three outbreaks caused by 2019-nCoV Omicron variant in Beijing, China.
10.3760/cma.j.cn112338-20221112-00966
- Author:
Shuang Sheng WU
1
;
Ying SUN
1
;
Xiang Feng DOU
1
;
Zhen Yong REN
1
;
Jiao Jiao ZHANG
1
;
Lei JIA
1
;
Peng YANG
2
;
Xing Huo PANG
2
Author Information
1. Institute for Infectious Disease and Endemic Disease Control, Beijing Municipal Center for Disease Prevention and Control, Beijing 100013, China.
2. Central Office, Beijing Municipal Center for Disease Prevention and Control, Beijing 100013, China.
- Publication Type:Journal Article
- MeSH:
Humans;
Beijing;
SARS-CoV-2;
COVID-19;
Disease Outbreaks;
China/epidemiology*
- From:
Chinese Journal of Epidemiology
2023;44(3):373-378
- CountryChina
- Language:Chinese
-
Abstract:
Objective: To investigate the infection sources and the transmission chains of three outbreaks caused by 2019-nCoV Omicron variant possibly spread through cross-border logistics in Beijing. Methods: Epidemiological investigation and big data were used to identify the exposure points of the cases. Close contacts were traced from the exposure points, and the cases' and environmental samples were collected for nucleic acid tests. Positive samples were analyzed by gene sequencing. Results: The Omicron variant causing 3 outbreaks in Beijing from January to April, 2022 belonged to BA.1, BA.1.1 and BA.2. The outbreaks lasted for 8, 12 and 8 days respectively, and 6, 42 and 32 cases infected with 2019-nCoV were reported respectively. International mail might be the infection source for 1 outbreak, and imported clothes might be the infection sources for another 2 outbreaks. The interval between the shipment start time of the imported goods and the infection time of the index case was 3-4 days. The mean incubation period (Q1, Q3) was 3 (2,4) days and the mean serial interval (Q1, Q3) was 3 (2,4)days. Conclusions: The 3 outbreaks highlighted the risk of infection by Omicron variant from international logistics-related imported goods at normal temperature. Omicron variant has stronger transmissibility, indicating that rapid epidemiological investigation and strict management are needed.
