Characterizing Infections in Two Epidemic Waves of SARS-CoV-2 Omicron Variants: A Cohort Study in Guangzhou, China
Lin Qu,
Chunyan Xie,
Ming Qiu,
Lina Yi,
Zhe Liu,
Lirong Zou,
Pei Hu,
Huimin Jiang,
Huimin Lian,
Mingda Yang,
Haiyi Yang,
Huiling Zeng,
Huimin Chen,
Jianguo Zhao,
Jianpeng Xiao,
Jianfeng He,
Ying Yang,
Liang Chen,
Baisheng Li,
Jiufeng Sun,
Jing Lu
Affiliations
Lin Qu
School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
Chunyan Xie
Guangdong Provincial Institution of Public Health, Guangzhou 511430, China
Ming Qiu
School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
Lina Yi
Guangdong Provincial Institution of Public Health, Guangzhou 511430, China
Zhe Liu
Guangdong Provincial Institution of Public Health, Guangzhou 511430, China
Lirong Zou
Guangdong Workstation for Emerging Infectious Disease Control and Prevention, Guangdong Provincial Key Laboratory of Pathogen Detection for Emerging Infectious Disease Response, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
Pei Hu
Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
Huimin Jiang
Guangdong Provincial Institution of Public Health, Guangzhou 511430, China
Huimin Lian
Guangdong Provincial Institution of Public Health, Guangzhou 511430, China
Mingda Yang
Guangdong Provincial Institution of Public Health, Guangzhou 511430, China
Haiyi Yang
School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
Huiling Zeng
Guangdong Provincial Institution of Public Health, Guangzhou 511430, China
Huimin Chen
Guangdong Provincial Institution of Public Health, Guangzhou 511430, China
Jianguo Zhao
Guangdong Provincial Institution of Public Health, Guangzhou 511430, China
Jianpeng Xiao
Guangdong Provincial Institution of Public Health, Guangzhou 511430, China
Jianfeng He
Guangdong Workstation for Emerging Infectious Disease Control and Prevention, Guangdong Provincial Key Laboratory of Pathogen Detection for Emerging Infectious Disease Response, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
Ying Yang
Guangdong Provincial Institution of Public Health, Guangzhou 511430, China
Liang Chen
Guangdong Provincial Institution of Public Health, Guangzhou 511430, China
Baisheng Li
Guangdong Workstation for Emerging Infectious Disease Control and Prevention, Guangdong Provincial Key Laboratory of Pathogen Detection for Emerging Infectious Disease Response, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou 511430, China
Jiufeng Sun
Guangdong Provincial Institution of Public Health, Guangzhou 511430, China
Jing Lu
School of Public Health, Sun Yat-sen University, Guangzhou 510080, China
Background: After the adjustment of COVID-19 epidemic policy, mainland China experienced two consecutive waves of Omicron variants within a seven-month period. In Guangzhou city, as one of the most populous regions, the viral infection characteristics, molecular epidemiology, and the dynamic of population immunity are still elusive. Methods: We launched a prospective cohort study in the Guangdong Provincial CDC from December 2022 to July 2023. Fifty participants who received the same vaccination regimen and had no previous infection were recruited. Results: 90% of individuals were infected with Omicron BA.5* variants within three weeks in the first wave. Thirteen cases (28.26%) experienced infection with XBB.1* variants, occurring from 14 weeks to 21 weeks after the first wave. BA.5* infections exhibited higher viral loads in nasopharyngeal sites compared to oropharyngeal sites. Compared to BA.5* infections, the XBB.1* infections had significantly milder clinical symptoms, lower viral loads, and shorter durations of virus positivity. The infection with the BA.5* variant elicited varying levels of neutralizing antibodies against XBB.1* among different individuals, even with similar levels of BA.5* antibodies. The level of neutralizing antibodies specific to XBB.1* determined the risk of reinfection. Conclusions: The rapid large-scale infections of the Omicron variants have quickly established herd immunity among the population in mainland China. In the future of the COVID-19 epidemic, a lower infection rate but a longer duration can be expected. Given the large population size and ongoing diversified herd immunity, it remains crucial to closely monitor the molecular epidemiology of SARS-CoV-2 for the emergence of new variants of concern in this region. Additionally, the timely evaluation of the immune status across different age groups is essential for informing future vaccination strategies and intervention policies.
