Nat Commun. 2022 Nov 11
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
Products used in the paper Details Operation
hACE2-expressed HEK293 cell lines Human ACE2 over-express HEK293T (hACE2-293T, PackGene Biotech) were cultured in DMEM (10-013-CVRC, Corning) supplemented with 10% fetal bovine serum (FBS, FSP500, ExCellBio), non-essential amino acids (NEAA, 11140-050, Gibco), 100 U/ml penicillin and 100 μg/ml streptomycin (SV30010, HyClone). Request Quote

Research Field: Covid-related

Keywords: Immunology, Medical research, SARS-CoV-2, Inactivated vaccines


The effectiveness of a 3rd dose 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 3rd dose. The primary and secondary outcomes are neutralizing antibodies (NAbs) and the receptor-binding domain (RBD)-directed antibodies, respectively. The 4th dose recalls waned immunity while having distinct effects on humoral responses to different antigens. The peak antibody response to the RBD induced by the 4th dose is inferior to that after the 3rd dose, whereas responses to the N-terminal domain (NTD) of spike protein are further strengthened significantly. Accordingly, the 4th dose 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.

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