Enhanced immunity against SARS-CoV-2 in returning Chinese individuals

作者：Yuan, Runyu; Chen, Huimin; Yi, Lina; Li, Xinxin; Hu, Ximing; Li, Xing; Zhang, Huan; Zhou, Pingping; Liang, Chumin; Lin, Huifang; Zeng, Lilian; Zhuang, Xue; Ruan, Qianqian; Chen, Yueling; Deng, Yingyin; Liu, Zhe; Lu, Jing; Xiao, Jianpeng; Chen, Liang; Xiao, Xincai; Li, Jing^*; Li, Baisheng^*; Li, Yan^*; He, Jianfeng^*; Sun, Jiufeng^*

来源：Human Vaccines & Immunotherapeutics, 2024, 20(1): 2300208.

DOI：10.1080/21645515.2023.2300208

• COVID-19
• SARS-CoV-2
• returning Chinese individuals
• Omicron
• neutralizing antibody
• memory T-cell response

Global COVID-19 vaccination programs effectively contained the fast spread of SARS-CoV-2. Characterizing the immunity status of returned populations will favor understanding the achievement of herd immunity and long-term management of COVID-19 in China. Individuals were recruited from 7 quarantine stations in Guangzhou, China. Blood and throat swab specimens were collected from participants, and their immunity status was determined through competitive ELISA, microneutralization assay and enzyme-linked FluoroSpot assay. A total of 272 subjects were involved in the questionnaire survey, of whom 235 (86.4%) were returning Chinese individuals and 37 (13.6%) were foreigners. Blood and throat swab specimens were collected from 108 returning Chinese individuals. Neutralizing antibodies against SARS-CoV-2 were detected in similar to 90% of returning Chinese individuals, either in the primary or the homologous and heterologous booster vaccination group. The serum NAb titers were significantly decreased against SARS-CoV-2 Omicron BA.5, BF.7, BQ.1 and XBB.1 compared with the prototype virus. However, memory T-cell responses, including specific IFN-gamma and IL-2 responses, were not different in either group. Smoking, alcohol consumption, SARS-CoV-2 infection, COVID-19 vaccination, and the time interval between last vaccination and sampling were independent influencing factors for NAb titers against prototype SARS-CoV-2 and variants of concern. The vaccine dose was the unique common influencing factor for Omicron subvariants. Enhanced immunity against SARS-CoV-2 was established in returning Chinese individuals who were exposed to reinfection and vaccination. Domestic residents will benefit from booster homologous or heterologous COVID-19 vaccination after reopening of China, which is also useful against breakthrough infection.

• 单位
  中山大学; 广东药学院; y; 南方医科大学; 广州医学院