Epidemiological characteristics and transmission dynamics of the outbreak caused by the SARS-CoV-2 Omicron variant in Shanghai, China: A descriptive study

作者：Zhiyuan Chen, Xiaowei Deng, Li‐Qun Fang, Kaiyuan Sun, Yanpeng Wu, Tian-Le Che, Junyi Zou, Jun Cai, Hengcong Liu, Yan Wang, Tao Wang, Yuyang Tian, Nan Zheng, Xuemei Yan, Ruijia Sun, Xiangyanyu Xu, Xiaoyu Zhou, Shijia Ge, Yuxia Liang, Lan Yi, Juan Yang, Juanjuan Zhang, Marco Ajelli, Hongjie Yu · 发表于：The Lancet Regional Health - Western Pacific · 年份：2022 · DOI：10.1016/j.lanwpc.2022.100592 · 被引用次数：124 · 研究领域：SARS-CoV-2 and COVID-19 Research、COVID-19 epidemiological studies、Infection Control and Ventilation

Background In early March 2022, a major outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant spread rapidly throughout Shanghai, China. Here we aimed to provide a description of the epidemiological characteristics and spatiotemporal transmission dynamics of the Omicron outbreak under the population-based screening and lockdown policies implemented in Shanghai. Methods We extracted individual information on SARS-CoV-2 infections reported between January 1 and May 31, 2022, and on the timeline of the adopted non-pharmaceutical interventions. The epidemic was divided into three phases: i) sporadic infections (January 1–February 28), ii) local transmission (March 1–March 31), and iii) city-wide lockdown (April 1 to May 31). We described the epidemic spread during these three phases and the subdistrict-level spatiotemporal distribution of the infections. To evaluate the impact on the transmission of SARS-CoV-2 of the adopted targeted interventions in Phase 2 and city-wide lockdown in Phase 3, we estimated the dynamics of the net reproduction number ( R t ). Findings A surge in imported infections in Phase 1 triggered cryptic local transmission of the Omicron variant in early March, resulting in the largest outbreak in mainland China since the original wave. A total of 626,000 SARS-CoV-2 infections were reported in 99.5% (215/216) of the subdistricts of Shanghai until the end of May. The spatial distribution of the infections was highly heter...