Epidemiological characteristics and transmission dynamics of the outbreak caused by the SARS-CoV-2 Omicron variant in Shanghai, China: A descriptive study
Summary: 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 dyn...
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| Format: | Article |
| Language: | English |
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Elsevier
2022-12-01
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| Series: | The Lancet Regional Health. Western Pacific |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666606522002073 |
| _version_ | 1798036893438312448 |
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| author | Zhiyuan Chen Xiaowei Deng Liqun Fang Kaiyuan Sun Yanpeng Wu Tianle 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 |
| author_facet | Zhiyuan Chen Xiaowei Deng Liqun Fang Kaiyuan Sun Yanpeng Wu Tianle 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 |
| author_sort | Zhiyuan Chen |
| collection | DOAJ |
| description | Summary: 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 (Rt). 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 heterogeneous, with 37% 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 463 to 244 meters/day) prior to the citywide lockdown. During Phase 2, Rt 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 Rt below the epidemic threshold in the entire city on April 14 and ultimately leading to containment of the outbreak. Interpretation: Our results highlight the risk of widespread outbreaks in mainland China, particularly under the heightened pressure of imported infections. The targeted interventions adopted in March 2022 were not capable of halting transmission, and the implementation of a strict, prolonged city-wide lockdown was needed to successfully contain the outbreak, highlighting the challenges for containing Omicron outbreaks. Funding: Key Program of the National Natural Science Foundation of China (82130093); Shanghai Rising-Star Program (22QA1402300). |
| first_indexed | 2024-04-11T21:19:13Z |
| format | Article |
| id | doaj.art-1e92eef61cef42fcbc17d1005391f1d2 |
| institution | Directory Open Access Journal |
| issn | 2666-6065 |
| language | English |
| last_indexed | 2024-04-11T21:19:13Z |
| publishDate | 2022-12-01 |
| publisher | Elsevier |
| record_format | Article |
| series | The Lancet Regional Health. Western Pacific |
| spelling | doaj.art-1e92eef61cef42fcbc17d1005391f1d22022-12-22T04:02:42ZengElsevierThe Lancet Regional Health. Western Pacific2666-60652022-12-0129100592Epidemiological characteristics and transmission dynamics of the outbreak caused by the SARS-CoV-2 Omicron variant in Shanghai, China: A descriptive studyZhiyuan Chen0Xiaowei Deng1Liqun Fang2Kaiyuan Sun3Yanpeng Wu4Tianle Che5Junyi Zou6Jun Cai7Hengcong Liu8Yan Wang9Tao Wang10Yuyang Tian11Nan Zheng12Xuemei Yan13Ruijia Sun14Xiangyanyu Xu15Xiaoyu Zhou16Shijia Ge17Yuxia Liang18Lan Yi19Juan Yang20Juanjuan Zhang21Marco Ajelli22Hongjie Yu23School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, ChinaSchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, ChinaState Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, ChinaDivision of International Epidemiology and Population Studies, Fogarty International Center, National Institutes of Health, Bethesda, MD, USASchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, ChinaState Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, ChinaSchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, ChinaSchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, ChinaSchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, ChinaSchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, ChinaState Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, ChinaSchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, ChinaSchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, ChinaSchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, ChinaSchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, ChinaSchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, ChinaSchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, ChinaDepartment of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, ChinaSchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, ChinaSchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, ChinaSchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China; Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, ChinaSchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China; Co-corresponding authors at: School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai 200032, China.Laboratory for Computational Epidemiology and Public Health, Department of Epidemiology and Biostatistics, Indiana University School of Public Health, Bloomington, IN, USASchool of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China; Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, China; Co-corresponding authors at: School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai 200032, China.Summary: 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 (Rt). 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 heterogeneous, with 37% 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 463 to 244 meters/day) prior to the citywide lockdown. During Phase 2, Rt 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 Rt below the epidemic threshold in the entire city on April 14 and ultimately leading to containment of the outbreak. Interpretation: Our results highlight the risk of widespread outbreaks in mainland China, particularly under the heightened pressure of imported infections. The targeted interventions adopted in March 2022 were not capable of halting transmission, and the implementation of a strict, prolonged city-wide lockdown was needed to successfully contain the outbreak, highlighting the challenges for containing Omicron outbreaks. Funding: Key Program of the National Natural Science Foundation of China (82130093); Shanghai Rising-Star Program (22QA1402300).http://www.sciencedirect.com/science/article/pii/S2666606522002073SARS-CoV-2OmicronShanghai outbreakNon-pharmaceutical interventionTransmission dynamics |
| spellingShingle | Zhiyuan Chen Xiaowei Deng Liqun Fang Kaiyuan Sun Yanpeng Wu Tianle 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 Epidemiological characteristics and transmission dynamics of the outbreak caused by the SARS-CoV-2 Omicron variant in Shanghai, China: A descriptive study The Lancet Regional Health. Western Pacific SARS-CoV-2 Omicron Shanghai outbreak Non-pharmaceutical intervention Transmission dynamics |
| title | Epidemiological characteristics and transmission dynamics of the outbreak caused by the SARS-CoV-2 Omicron variant in Shanghai, China: A descriptive study |
| title_full | Epidemiological characteristics and transmission dynamics of the outbreak caused by the SARS-CoV-2 Omicron variant in Shanghai, China: A descriptive study |
| title_fullStr | Epidemiological characteristics and transmission dynamics of the outbreak caused by the SARS-CoV-2 Omicron variant in Shanghai, China: A descriptive study |
| title_full_unstemmed | Epidemiological characteristics and transmission dynamics of the outbreak caused by the SARS-CoV-2 Omicron variant in Shanghai, China: A descriptive study |
| title_short | Epidemiological characteristics and transmission dynamics of the outbreak caused by the SARS-CoV-2 Omicron variant in Shanghai, China: A descriptive study |
| title_sort | epidemiological characteristics and transmission dynamics of the outbreak caused by the sars cov 2 omicron variant in shanghai china a descriptive study |
| topic | SARS-CoV-2 Omicron Shanghai outbreak Non-pharmaceutical intervention Transmission dynamics |
| url | http://www.sciencedirect.com/science/article/pii/S2666606522002073 |
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