‘Dynamic zero-COVID’ policy and viral clearance during an omicron wave in Tianjin, China: a city-wide retrospective observational study
Objective To report how the Chinese mainland battled its first omicron wave, which happened in Tianjin, a metropolis with 14 million residents. We also sought to better understand how clinical features affected the timing of viral clearance.Design A retrospective study of the omicron wave in Tianjin...
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BMJ Publishing Group
2022-12-01
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| Series: | BMJ Open |
| Online Access: | https://bmjopen.bmj.com/content/12/12/e066359.full |
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| author | Qi Wu Yan Xie Tao Cheng Junping Wu Wentao Jiang Lixia Shi Xiaolong Liu Yu Hu Yahui Feng Hongxia Shao Xiaowen Gong Zhen Song Saibing Qi Xueou Liu Qiujin Shen Junren Chen |
| author_facet | Qi Wu Yan Xie Tao Cheng Junping Wu Wentao Jiang Lixia Shi Xiaolong Liu Yu Hu Yahui Feng Hongxia Shao Xiaowen Gong Zhen Song Saibing Qi Xueou Liu Qiujin Shen Junren Chen |
| author_sort | Qi Wu |
| collection | DOAJ |
| description | Objective To report how the Chinese mainland battled its first omicron wave, which happened in Tianjin, a metropolis with 14 million residents. We also sought to better understand how clinical features affected the timing of viral clearance.Design A retrospective study of the omicron wave in Tianjin between 8 January 2022 and 3 March 2022.Setting Except for the first cases on 8 January, all the omicron cases were identified through PCR mass testing in the residential communities. Residential quarantine and serial PCR mass testing were dynamically adjusted according to the trends of new cases.Participants All the 417 consecutive PCR-positive cases identified through mass screening of the entire city’s 14 million residents. 45.3% of the cases were male, and the median age was 37 (range 0.3–90). 389 (93%) cases had complete data for analysing the correlation between clinical features and the timing of viral clearance.Main outcome and measure Time to viral clearance.Results Tianjin initiated the ‘dynamic zero-COVID’ policy very early, that is, when daily new case number was ≈0.4 cases per 1 000 000 residents. Daily new cases dropped to <5 after 3 February, and the number of affected residential subdivisions dropped to ≤2 after 13 February. 64% (267/417) of the cases had no or mild symptoms. The median interval from hospital admission to viral clearance was 10 days (range 3–28). An exploratory analysis identified a feature cluster associated with earlier viral clearance, with HRs of 3.56 (95% CI 1.66 to 7.63) and 3.15 (95% CI 1.68 to 5.91) in the training and validation sets, respectively.Conclusions The ‘dynamic zero-COVID’ policy can suppress an omicron wave within a month. It might be possible to predict in advance which cases will require shorter periods of isolation based on their clinical features. |
| format | Article |
| id | doaj-art-22042ebacc6d475aba85aee363d472ea |
| institution | Kabale University |
| issn | 2044-6055 |
| language | English |
| publishDate | 2022-12-01 |
| publisher | BMJ Publishing Group |
| record_format | Article |
| series | BMJ Open |
| spelling | doaj-art-22042ebacc6d475aba85aee363d472ea2025-02-02T00:00:11ZengBMJ Publishing GroupBMJ Open2044-60552022-12-01121210.1136/bmjopen-2022-066359‘Dynamic zero-COVID’ policy and viral clearance during an omicron wave in Tianjin, China: a city-wide retrospective observational studyQi Wu0Yan Xie1Tao Cheng2Junping Wu3Wentao Jiang4Lixia Shi5Xiaolong Liu6Yu Hu7Yahui Feng8Hongxia Shao9Xiaowen Gong10Zhen Song11Saibing Qi12Xueou Liu13Qiujin Shen14Junren Chen15Department of Breast and Thyroid Surgery, Renmin Hospital of Wuhan University, Wuhan, Hubei, China2 Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, ChinaState Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, ChinaShanghai Ji Ai Genetics & IVF Institute, Obstetrics and Gynecology Hospital, Fudan University, Shanghai, Shanghai, China3 Department of Liver Transplantation, Tianjin First Center Hospital, Tianjin Key Laboratory for Organ Transplantation, Key Laboratory of Transplantation, Chinese Academy of Medical Sciences, Tianjin, ChinaDepartment of Infectious Disease, Haihe Clinical School, Tianjin Medical University, Tianjin, ChinaDepartment of Infectious Disease, Haihe Clinical School, Tianjin Medical University, Tianjin, ChinaState Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, ChinaState Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, ChinaDepartment of Infectious Disease, Haihe Clinical School, Tianjin Medical University, Tianjin, ChinaState Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, ChinaState Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, ChinaState Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, ChinaState Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, ChinaState Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, ChinaState Key Laboratory of Experimental Hematology, National Clinical Research Center for Blood Diseases, Haihe Laboratory of Cell Ecosystem, Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, ChinaObjective To report how the Chinese mainland battled its first omicron wave, which happened in Tianjin, a metropolis with 14 million residents. We also sought to better understand how clinical features affected the timing of viral clearance.Design A retrospective study of the omicron wave in Tianjin between 8 January 2022 and 3 March 2022.Setting Except for the first cases on 8 January, all the omicron cases were identified through PCR mass testing in the residential communities. Residential quarantine and serial PCR mass testing were dynamically adjusted according to the trends of new cases.Participants All the 417 consecutive PCR-positive cases identified through mass screening of the entire city’s 14 million residents. 45.3% of the cases were male, and the median age was 37 (range 0.3–90). 389 (93%) cases had complete data for analysing the correlation between clinical features and the timing of viral clearance.Main outcome and measure Time to viral clearance.Results Tianjin initiated the ‘dynamic zero-COVID’ policy very early, that is, when daily new case number was ≈0.4 cases per 1 000 000 residents. Daily new cases dropped to <5 after 3 February, and the number of affected residential subdivisions dropped to ≤2 after 13 February. 64% (267/417) of the cases had no or mild symptoms. The median interval from hospital admission to viral clearance was 10 days (range 3–28). An exploratory analysis identified a feature cluster associated with earlier viral clearance, with HRs of 3.56 (95% CI 1.66 to 7.63) and 3.15 (95% CI 1.68 to 5.91) in the training and validation sets, respectively.Conclusions The ‘dynamic zero-COVID’ policy can suppress an omicron wave within a month. It might be possible to predict in advance which cases will require shorter periods of isolation based on their clinical features.https://bmjopen.bmj.com/content/12/12/e066359.full |
| spellingShingle | Qi Wu Yan Xie Tao Cheng Junping Wu Wentao Jiang Lixia Shi Xiaolong Liu Yu Hu Yahui Feng Hongxia Shao Xiaowen Gong Zhen Song Saibing Qi Xueou Liu Qiujin Shen Junren Chen ‘Dynamic zero-COVID’ policy and viral clearance during an omicron wave in Tianjin, China: a city-wide retrospective observational study BMJ Open |
| title | ‘Dynamic zero-COVID’ policy and viral clearance during an omicron wave in Tianjin, China: a city-wide retrospective observational study |
| title_full | ‘Dynamic zero-COVID’ policy and viral clearance during an omicron wave in Tianjin, China: a city-wide retrospective observational study |
| title_fullStr | ‘Dynamic zero-COVID’ policy and viral clearance during an omicron wave in Tianjin, China: a city-wide retrospective observational study |
| title_full_unstemmed | ‘Dynamic zero-COVID’ policy and viral clearance during an omicron wave in Tianjin, China: a city-wide retrospective observational study |
| title_short | ‘Dynamic zero-COVID’ policy and viral clearance during an omicron wave in Tianjin, China: a city-wide retrospective observational study |
| title_sort | dynamic zero covid policy and viral clearance during an omicron wave in tianjin china a city wide retrospective observational study |
| url | https://bmjopen.bmj.com/content/12/12/e066359.full |
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