Incidence of SARS-CoV-2 infection in children shortly after ending zero-COVID-19 policy in China on December 7, 2022: a cross-sectional, multicenter, seroepidemiological study
BackgroundChina discontinued the zero-COVID-19 policy on December 7, 2022, and then COVID-19 surged mid-December 2022 through mid-January 2023. However, the actual incidence was unknown. This study aimed to estimate the incidence of SARS-CoV-2 infection in children shortly after ending the zero-COVI...
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Frontiers Media S.A.
2023-11-01
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| Series: | Frontiers in Public Health |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fpubh.2023.1283158/full |
| _version_ | 1827763854246936576 |
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| author | Yi-Hua Zhou Chenyu Xu Yue Tao Meng Gu Guiping Zhou Wei Zhou Yue Jin Jun Xie Biyun Xu Wensan Zhou Junhao Chen Weifeng Shi |
| author_facet | Yi-Hua Zhou Chenyu Xu Yue Tao Meng Gu Guiping Zhou Wei Zhou Yue Jin Jun Xie Biyun Xu Wensan Zhou Junhao Chen Weifeng Shi |
| author_sort | Yi-Hua Zhou |
| collection | DOAJ |
| description | BackgroundChina discontinued the zero-COVID-19 policy on December 7, 2022, and then COVID-19 surged mid-December 2022 through mid-January 2023. However, the actual incidence was unknown. This study aimed to estimate the incidence of SARS-CoV-2 infection in children shortly after ending the zero-COVID-19 policy.MethodsThis multicenter cross-sectional study included 1,065 children aged 8 months to 12 years from seven hospitals at six regions across Jiangsu province, based on the convenience sampling, from February 10 to March 10, 2023. Group I comprised 324 children aged 8 months–2 years without COVID-19 vaccination, group II consisted of 338 preschool children aged 3–5 years with varied vaccination history, and group III contained 403 primary school children aged 6–12 years with mostly vaccinated. The COVID-19 vaccines were composed of inactivated SARS-CoV-2. In addition, 96 children’s sera collected in 2014 were included as negative controls. IgG and IgM antibodies against nucleocapsid (N) and subunit 1 of spike (S1) of SARS-CoV-2 (anti-N/S1) were measured with commercial kits (YHLO Biotech, Shenzhen, China).ResultsNone of the 96 children (5.1 ± 3.5 years; 58.3% boys) in 2014 was positive for anti-N/S1 IgG or IgM. Of the 1,065 children (5.0 ± 3.5 years; 56.0% boys), 988 (92.8%) were anti-N/S1 IgG positive but none was anti-N/S1 IgM positive. The positive rate of anti-N/S1 IgG in Group I, II, and III was 90.4, 88.5, and 98.3%, respectively, with significantly higher in group III than in groups I and II (p < 0.0001). The median antibody titers in group III (381.61 AU/ml) were much higher than that in group I (38.34 AU/ml) and II (51.88 AU/ml; p < 0.0001).ConclusionMore than 90% children experienced SARS-CoV-2 infection shortly after ending zero-COVID-19 policy in China, much higher than estimated infections by other studies. The widespread SARS-CoV-2 infection in unvaccinated children should be influential on the policy of COVID-19 vaccination in children in the future. |
| first_indexed | 2024-03-11T10:56:35Z |
| format | Article |
| id | doaj.art-c4de0b1e8f4c4e7ba3e99c6dd744ac21 |
| institution | Directory Open Access Journal |
| issn | 2296-2565 |
| language | English |
| last_indexed | 2024-03-11T10:56:35Z |
| publishDate | 2023-11-01 |
| publisher | Frontiers Media S.A. |
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| series | Frontiers in Public Health |
| spelling | doaj.art-c4de0b1e8f4c4e7ba3e99c6dd744ac212023-11-13T06:35:11ZengFrontiers Media S.A.Frontiers in Public Health2296-25652023-11-011110.3389/fpubh.2023.12831581283158Incidence of SARS-CoV-2 infection in children shortly after ending zero-COVID-19 policy in China on December 7, 2022: a cross-sectional, multicenter, seroepidemiological studyYi-Hua Zhou0Chenyu Xu1Yue Tao2Meng Gu3Guiping Zhou4Wei Zhou5Yue Jin6Jun Xie7Biyun Xu8Wensan Zhou9Junhao Chen10Weifeng Shi11Departments of Laboratory Medicine and Infectious Diseases, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, and Jiangsu Key Laboratory for Molecular Medicine, Nanjing University, Nanjing, Jiangsu, ChinaDepartment of Obstetrics and Gynecology, Zhenjiang Fourth People’s Hospital, Zhenjiang, Jiangsu, ChinaDepartments of Laboratory Medicine and Infectious Diseases, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, and Jiangsu Key Laboratory for Molecular Medicine, Nanjing University, Nanjing, Jiangsu, ChinaDepartment of Clinical Laboratory, Affiliated Changzhou Children's Hospital of Nantong University, Changzhou Children's Hospital, Changzhou, Jiangsu, ChinaDepartment of Clinical Laboratory, Yixing Second People’s Hospital, Yixing, Jiangsu, ChinaDepartment of Clinical Laboratory, The First People’s Hospital of Changzhou, Changzhou, Jiangsu, ChinaDepartment of Clinical Laboratory, Huai'an Second People's Hospital and the Affiliated Huai'an Hospital of Xuzhou Medical University, Huai’an, Jiangsu, ChinaDepartment of Clinical Laboratory, People's Hospital of Xuyi County, Xuyi, Jiangsu, ChinaMedical Statistics and Analysis Center, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, Jiangsu, ChinaDepartments of Laboratory Medicine and Infectious Diseases, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, and Jiangsu Key Laboratory for Molecular Medicine, Nanjing University, Nanjing, Jiangsu, ChinaDepartments of Laboratory Medicine and Infectious Diseases, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, and Jiangsu Key Laboratory for Molecular Medicine, Nanjing University, Nanjing, Jiangsu, ChinaDepartment of Clinical Laboratory, The First People’s Hospital of Changzhou, Changzhou, Jiangsu, ChinaBackgroundChina discontinued the zero-COVID-19 policy on December 7, 2022, and then COVID-19 surged mid-December 2022 through mid-January 2023. However, the actual incidence was unknown. This study aimed to estimate the incidence of SARS-CoV-2 infection in children shortly after ending the zero-COVID-19 policy.MethodsThis multicenter cross-sectional study included 1,065 children aged 8 months to 12 years from seven hospitals at six regions across Jiangsu province, based on the convenience sampling, from February 10 to March 10, 2023. Group I comprised 324 children aged 8 months–2 years without COVID-19 vaccination, group II consisted of 338 preschool children aged 3–5 years with varied vaccination history, and group III contained 403 primary school children aged 6–12 years with mostly vaccinated. The COVID-19 vaccines were composed of inactivated SARS-CoV-2. In addition, 96 children’s sera collected in 2014 were included as negative controls. IgG and IgM antibodies against nucleocapsid (N) and subunit 1 of spike (S1) of SARS-CoV-2 (anti-N/S1) were measured with commercial kits (YHLO Biotech, Shenzhen, China).ResultsNone of the 96 children (5.1 ± 3.5 years; 58.3% boys) in 2014 was positive for anti-N/S1 IgG or IgM. Of the 1,065 children (5.0 ± 3.5 years; 56.0% boys), 988 (92.8%) were anti-N/S1 IgG positive but none was anti-N/S1 IgM positive. The positive rate of anti-N/S1 IgG in Group I, II, and III was 90.4, 88.5, and 98.3%, respectively, with significantly higher in group III than in groups I and II (p < 0.0001). The median antibody titers in group III (381.61 AU/ml) were much higher than that in group I (38.34 AU/ml) and II (51.88 AU/ml; p < 0.0001).ConclusionMore than 90% children experienced SARS-CoV-2 infection shortly after ending zero-COVID-19 policy in China, much higher than estimated infections by other studies. The widespread SARS-CoV-2 infection in unvaccinated children should be influential on the policy of COVID-19 vaccination in children in the future.https://www.frontiersin.org/articles/10.3389/fpubh.2023.1283158/fullantibody to SARS-CoV-19prevalencechildrenCOVID-19 vaccinationdiscontinuation of zero-COVID-19 policy |
| spellingShingle | Yi-Hua Zhou Chenyu Xu Yue Tao Meng Gu Guiping Zhou Wei Zhou Yue Jin Jun Xie Biyun Xu Wensan Zhou Junhao Chen Weifeng Shi Incidence of SARS-CoV-2 infection in children shortly after ending zero-COVID-19 policy in China on December 7, 2022: a cross-sectional, multicenter, seroepidemiological study Frontiers in Public Health antibody to SARS-CoV-19 prevalence children COVID-19 vaccination discontinuation of zero-COVID-19 policy |
| title | Incidence of SARS-CoV-2 infection in children shortly after ending zero-COVID-19 policy in China on December 7, 2022: a cross-sectional, multicenter, seroepidemiological study |
| title_full | Incidence of SARS-CoV-2 infection in children shortly after ending zero-COVID-19 policy in China on December 7, 2022: a cross-sectional, multicenter, seroepidemiological study |
| title_fullStr | Incidence of SARS-CoV-2 infection in children shortly after ending zero-COVID-19 policy in China on December 7, 2022: a cross-sectional, multicenter, seroepidemiological study |
| title_full_unstemmed | Incidence of SARS-CoV-2 infection in children shortly after ending zero-COVID-19 policy in China on December 7, 2022: a cross-sectional, multicenter, seroepidemiological study |
| title_short | Incidence of SARS-CoV-2 infection in children shortly after ending zero-COVID-19 policy in China on December 7, 2022: a cross-sectional, multicenter, seroepidemiological study |
| title_sort | incidence of sars cov 2 infection in children shortly after ending zero covid 19 policy in china on december 7 2022 a cross sectional multicenter seroepidemiological study |
| topic | antibody to SARS-CoV-19 prevalence children COVID-19 vaccination discontinuation of zero-COVID-19 policy |
| url | https://www.frontiersin.org/articles/10.3389/fpubh.2023.1283158/full |
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