Emerging Microbes and Infections (Dec 2023)

Neutralization against Omicron subvariants after BA.5/BF.7 breakthrough infection weakened as virus evolution and aging despite repeated prototype-based vaccination1

  • Hongyu Wang,
  • Quanlin Xue,
  • Haocheng Zhang,
  • Guanmin Yuan,
  • Xun Wang,
  • Kai Sheng,
  • Chen Li,
  • Jianpeng Cai,
  • Yuhan Sun,
  • Jingjing Zhao,
  • Jiahuan Lu,
  • Shuyu Fang,
  • Yongfeng Yang,
  • Yeting Zhang,
  • Ying Huang,
  • Jiancui Wang,
  • Jonathan H. Xu,
  • Melissa X. Jiang,
  • Xinyu Wang,
  • Lei Shen,
  • Yuanyuan Liu,
  • Qihui Liu,
  • Qiran Zhang,
  • Sen Wang,
  • Pengfei Wang,
  • Chao Qiu,
  • Jingwen Ai,
  • Wenhong Zhang

DOI
https://doi.org/10.1080/22221751.2023.2249121
Journal volume & issue
Vol. 12, no. 2

Abstract

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Background: Omicron had swept the mainland China between December 2022 and January 2023, while SARS-CoV-2 still continued to evolve. To fully prepare for the next wave, it’s urgent to evaluate the humoral immune response post BA.5/BF.7 breakthrough infection against predominant sub-lineages among existing vaccination strategies and the elders. Method: This study enrolled a longitudinal young-adult cohort from 2/3-dose vaccination to 1 month after breakthrough infection, and an elder cohort at 1 month after breakthrough infection. Seral samples were collected and tested for humoral immune response to SARS-CoV-2 subvariants including WT, BA.2, BA.5, BF.7, BQ.1.1, CH.1.1, XBB.1.5. Results: BA.5/BF.7 breakthrough infection induced higher neutralization activity than solely vaccination in all SARS-CoV-2 strains, while the latest Omicron subvariants, BQ.1.1, CH.1.1, XBB.1.5, exhibited the strongest neutralization evasion ability. There was a negative correlation between age and humoral immune response in WT, BA.5, BQ.1.1, and XBB.1.5. Compared to non-vaccination groups, breakthrough infection in two-dose vaccination groups had significantly higher neutralizing antibody against WT, BA.2, BA.5, BF.7 but not to BQ.1.1, CH.1.1, XBB.1.5 while booster dose against the prototype prior-breakthrough would not further significantly enhance individual’s humoral responses against the latest Omicron subvariants. Conclusions: Newer variants manifest increasing immune evasion from neutralization and repeated prototype-based booster vaccines may not further enhance neutralizing antibody against emerging new variants. Older adults have lower levels of neutralizing antibody. Future vaccination strategies should aim to enhance effective neutralization to contemporary variants.

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