Article
SARS-CoV-2 Omicron variant escapes neutralizing antibodies and T cell responses more efficiently than other variants in mild COVID-19 convalescents

https://doi.org/10.1016/j.xcrm.2022.100651Get rights and content
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Highlights

  • Most mild COVID-19 convalescents maintain immunity at 12 months after disease onset

  • B.1.1.529 escapes antibodies in convalescents infected with ancestral SARS-CoV-2

  • SARS-CoV-2 VOCs can partially avoid recognition by antigen-specific T cells

  • Antigenic drift in SARS-CoV-2 VOCs significantly challenges convalescent immunity

Summary

Coronavirus disease 2019 (COVID-19) convalescents living in regions with low vaccination rates rely on post-infection immunity for protection against re-infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We evaluate humoral and T cell immunity against five variants of concern (VOCs) in mild-COVID-19 convalescents at 12 months after infection with ancestral virus. In this cohort, ancestral, receptor-binding domain (RBD)-specific antibody and circulating memory B cell levels are conserved in most individuals, and yet serum neutralization against live B.1.1.529 (Omicron) is completely abrogated and significantly reduced for other VOCs. Likewise, ancestral SARS-CoV-2-specific memory T cell frequencies are maintained in >50% of convalescents, but the cytokine response in these cells to mutated spike epitopes corresponding to B.1.1.529 and B.1.351 (Beta) VOCs were impaired. These results indicate that increased antigen variability in VOCs impairs humoral and spike-specific T cell immunity post-infection, strongly suggesting that COVID-19 convalescents are vulnerable and at risk of re-infection with VOCs, thus stressing the importance of vaccination programs.

Keywords

SARS-CoV-2
T cell immunity
memory B cells
antibody response
virus neutralization
Variant of Concern
antigen drift

Data and code availability

Any additional information required to reanalyze the data reported in this paper is available from the lead contact upon request.

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18

These authors contributed equally

19

Lead contact