1. A fourth dose of the inactivated SARS-CoV-2 vaccine redistributes humoral immunity to the N-terminal domain
- Author
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Ji Wang, Caiguangxi Deng, Ming Liu, Yihao Liu, Liubing Li, Zhangping Huang, Liru Shang, Juan Jiang, Yongyong Li, Ruohui Mo, Hui Zhang, Min Liu, Sui Peng, and Haipeng Xiao
- Subjects
Multidisciplinary ,COVID-19 Vaccines ,Membrane Glycoproteins ,SARS-CoV-2 ,General Physics and Astronomy ,COVID-19 ,Viral Vaccines ,General Chemistry ,Antibodies, Viral ,Antibodies, Neutralizing ,General Biochemistry, Genetics and Molecular Biology ,Immunity, Humoral ,Vaccines, Inactivated ,Viral Envelope Proteins ,Spike Glycoprotein, Coronavirus ,Humans - Abstract
The effectiveness of a 3rddose of SARS-CoV-2 vaccines waned quickly in the Omicron-predominant period. In response to fast-waning immunity and the threat of Omicron variant of concern (VOC) to healthcare workers (HCWs), we conduct a non-randomized trial (ChiCTR2200055564) in which 38 HCWs volunteer to receive a homologous booster of inactivated vaccines (BBIBP-CorV) 6 months after the 3rddose. The primary and secondary outcomes are neutralizing antibodies (NAbs) and the receptor-binding domain (RBD)-directed antibodies, respectively. The 4thdose recalls waned immunity while having distinct effects on humoral responses to different antigens. The peak antibody response to the RBD induced by the 4thdose is inferior to that after the 3rddose, whereas responses to the N-terminal domain (NTD) of spike protein are further strengthened significantly. Accordingly, the 4thdose further elevates the peak level of NAbs against ancestral SARS-CoV-2 and Omicron BA.2, but not BA.1 which has more NTD mutations. No severe adverse events related to vaccination are recorded during the trial. Here, we show that redistribution of immune focus after repeated vaccinations may modulate cross-protective immune responses against different VOCs.
- Published
- 2022