Antibody seroprevalence in the epicenter Wuhan, Hubei, and six selected provinces after containment of the first epidemic wave of COVID-19 in China

Zhongjie Li; Xuhua Guan; Naiying Mao; Huiming Luo; Ying Qin; Na He; Zhen Zhu; Jianxing Yu; Yu Li; Jianhua Liu; Zhijie An; Wenjing Gao; Xiaoli Wang; Xiaodong Sun; Tie Song; Xingfen Yang; Ming Wu; Xianping Wu; Wenqing Yao; Zhibin Peng; Junling Sun; Liping Wang; Qing Guo; Nijuan Xiang; Jun Liu; Bike Zhang; Xuemei Su; Lance Rodewald; Liming Li; Wenbo Xu; Hongbing Shen; Zijian Feng; George F Gao

doi:10.1016/j.lanwpc.2021.100094

Antibody seroprevalence in the epicenter Wuhan, Hubei, and six selected provinces after containment of the first epidemic wave of COVID-19 in China

Lancet Reg Health West Pac. 2021 Mar:8:100094. doi: 10.1016/j.lanwpc.2021.100094. Epub 2021 Feb 5.

Authors

Zhongjie Li¹, Xuhua Guan², Naiying Mao³, Huiming Luo¹, Ying Qin¹, Na He⁴, Zhen Zhu³, Jianxing Yu⁵, Yu Li¹, Jianhua Liu⁶, Zhijie An⁷, Wenjing Gao⁸, Xiaoli Wang⁹, Xiaodong Sun¹⁰, Tie Song¹¹, Xingfen Yang¹², Ming Wu¹³, Xianping Wu¹⁴, Wenqing Yao¹⁵, Zhibin Peng¹, Junling Sun¹, Liping Wang¹, Qing Guo¹, Nijuan Xiang¹, Jun Liu¹, Bike Zhang¹, Xuemei Su^{1

9}, Lance Rodewald¹, Liming Li^{16

8}, Wenbo Xu³, Hongbing Shen¹⁷, Zijian Feng¹, George F Gao¹

Affiliations

¹ Chinese Center for Disease Control and Prevention (China CDC), Beijing, China.
² Hubei Provincial Center for Disease Control and Prevention, Wuhan, Hubei, China.
³ National Institute for Viral Disease Control and Prevention (China CDC), Beijing, China.
⁴ Fudan University, Shanghai, China.
⁵ National Institute for Communicable Disease Control and Prevention (China CDC), Beijing, China.
⁶ Guangzhou Municipal Center for Disease Control and Prevention, Guangzhou, Guangdong, China.
⁷ National Immunization Programme (China CDC), Beijing, China.
⁸ Department of Epidemiology and Biostatistics, School of Public Health, Peking University Health Science Center, Beijing, China.
⁹ Beijing Center for Disease Control and Prevention, Beijing, China.
¹⁰ Shanghai Center for Disease Control and Prevention, Shanghai, China.
¹¹ Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, Guangdong, China.
¹² School of Public Health, Southern Medical University, Guangzhou, Guangdong, China.
¹³ Jiangsu Provincial Center for Disease Control and Prevention, Nanjing, Jiangsu, China.
¹⁴ Sichuan Provincial Center for Disease Control and Prevention, Chengdu, Sichuan, China.
¹⁵ Liaoning Provincial Center for Disease Control and Prevention, Shenyang, Liaoning, China.
¹⁶ Peking University Center for Public Health and Epidemic Preparedness & Response.
¹⁷ Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China.

Abstract

Background: China implemented containment measures to stop SARS-CoV-2 transmission in response to the COVID-19 epidemic. After the first epidemic wave, we conducted population-based serological surveys to determine extent of infection, risk factors for infection, and neutralization antibody levels to assess the real infections in the random sampled population.

Methods: We used a multistage, stratified cluster random sampling strategy to conduct serological surveys in three areas - Wuhan, Hubei Province outside Wuhan, and six provinces selected on COVID-19 incidence and containment strategy. Participants were consenting individuals >1 year old who resided in the survey area >14 days during the epidemic. Provinces screened sera for SARS-CoV-2-specific IgM, IgG, and total antibody by two lateral flow immunoassays and one magnetic chemiluminescence enzyme immunoassay; positive samples were verified by micro-neutralization assay.

Findings: We enrolled 34,857 participants (overall response rate, 92%); 427 were positive by micro-neutralization assay. Wuhan had the highest weighted seroprevalence (4•43%, 95% confidence interval [95%CI]=3•48%-5•62%), followed by Hubei-ex-Wuhan (0•44%, 95%CI=0•26%-0•76%), and the other provinces (<0•1%). Living in Wuhan (adjusted odds ratio aOR=13•70, 95%CI= 7•91-23•75), contact with COVID-19 patients (aOR=7•35, 95%CI=5•05-10•69), and age over 40 (aOR=1•36, 95%CI=1•07-1•72) were significantly associated with SARS-CoV-2 infection. Among seropositives, 101 (24%) reported symptoms and had higher geometric mean neutralizing antibody titers than among the 326 (76%) without symptoms (30±2•4 vs 15±2•1, p<0•001).

Interpretation: The low overall extent of infection and steep gradient of seropositivity from Wuhan to the outer provinces provide evidence supporting the success of containment of the first wave of COVID-19 in China. SARS-CoV-2 infection was largely asymptomatic, emphasizing the importance of active case finding and physical distancing. Virtually the entire population of China remains susceptible to SARS-CoV-2; vaccination will be needed for long-term protection.

Funding: This study was supported by the Ministry of Science and Technology (2020YFC0846900) and the National Natural Science Foundation of China (82041026, 82041027, 82041028, 82041029, 82041030, 82041032, 82041033).