Seroprevalence and influencing factors of low-level neutralizing antibodies against SARS-CoV-2 in community residents

• Published in: Shanghai Yufang Yixue Vol. 37; no. 5; pp. 403 - 409
• Main Authors: YUAN Shiying, ZHANG Jingyi, WU Huanyu, WANG Weibing, ZHAO Genming, YU Xiao, MA Xiaoying, CHEN Min, SUN Xiaodong, HUANG Zhuoying, MA Zhonghui, ZHENG Yaxu, CHEN Jian
• Format: Journal Article
• Language: Chinese; English
• Published: Shanghai Preventive Medicine Association 01.05.2025
• Subjects: booster immunization; low-level; neutralizing antibody (nab); sars-cov-2
• ISSN: 1004-9231
• DOI: 10.19428/j.cnki.sjpm.2025.24689

ObjectiveTo understand the seropositivity of neutralizing antibodies (NAb) and low-level NAb against SARS-CoV-2 infection in the community residents, and to explore the impact of COVID-19 vaccination and SARS-CoV-2 infection on the levels of NAb in human serum.MethodsOn the ground of surveillance cohort for acute infectious diseases in community populations in Shanghai, a proportional stratified sampling method was used to enroll the subjects at a 20% proportion for each age group (0‒14, 15‒24, 25‒59, and ≥60 years old). Blood samples collection and serum SARS-CoV-2 NAb concentration testing were conducted from March to April 2023. Low-level NAb were defined as below the 25th percentile of NAb.ResultsA total of 2 230 participants were included, the positive rate of NAb was 97.58%, and the proportion of low-level NAb was 25.02% (558/2 230). Multivariate logistic regression analysis indicated that age, infection history and vaccination status were correlated with low-level NAb (all P<0.05). Individuals aged 60 years and above had the highest risk of low-level NAb. There was a statistically significant interaction between booster vaccination and one single infection (aOR=0.38, 95%CI: 0.19‒0.77). Compared to individuals without vaccination, among individuals infected with SARS-CoV-2 once, both primary immunization (aOR=0.23, 95%CI: 0.16‒0.35) and booster immunization (aOR=0.12, 95%CI: 0.08‒0.17) significantly reduced the risk of low-level NAb; among individuals without infections, only booster immunization (aOR=0.28, 95%CI: 0.14‒0.52) showed a negative correlation with the risk of low-level NAb.ConclusionsThe population aged 60 and above had the highest risk of low-level NAb. Regardless of infection history, a booster immunization could reduce the risk of low-level NAb. It is recommended that eligible individuals , especially the elderly, should get vaccinated in a timely manner to exert the protective role of NAb.