Epidemiological characteristics and transmission dynamics of the outbreak caused by the SARS-CoV-2 Omicron variant in Shanghai, China: a descriptive study
In: medRxiv, 2022
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Zugriff:
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-pharmacological 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 coronavirus disease 2019 (COVID-19) 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. The spatial distribution of the infections was highly heterogeneous, with 40% of the subdistricts accounting for 80% of all infections. A clear trend from the city center towards adjacent suburban and rural areas was observed, with a progressive slowdown of the epidemic spread (from 544 to 325 meters/day) prior to the citywide lockdown. During Phase 2, R(t) remained well above 1 despite the implementation of multiple targeted interventions. The citywide lockdown imposed on April 1 led to a marked decrease in transmission, bringing R(t) below the epidemic threshold in the entire .
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Epidemiological characteristics and transmission dynamics of the outbreak caused by the SARS-CoV-2 Omicron variant in Shanghai, China: a descriptive study
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Autor/in / Beteiligte Person: | Chen, Zhiyuan ; Deng, Xiaowei ; Fang, Liqun ; Sun, Kaiyuan ; Wu, Yanpeng ; Che, Tianle ; Zou, Junyi ; Cai, Jun ; Liu, Hengcong ; Wang, Yan ; Wang, Tao ; Tian, Yuyang ; Zheng, Nan ; Yan, Xuemei ; Sun, Ruijia ; Xu, Xiangyanyu ; Zhou, Xiaoyu ; Ge, Shijia ; Liang, Yuxiang ; Yi, Lan ; Yang, Juan ; Zhang, Juanjuan ; Ajelli, Marco ; Yu, Hongjie |
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Zeitschrift: | medRxiv, 2022 |
Veröffentlichung: | Cold Spring Harbor Laboratory, 2022 |
Medientyp: | academicJournal |
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