SARS-CoV-2 vaccination induces immunological memory able to cross-recognize variants from Alpha to Omicron

SUMMARY

We address whether T cell responses induced by different vaccine platforms (mRNA-1273, BNT162b2, Ad26.COV2.S, NVX-CoV2373) cross-recognize SARS-CoV-2 variants. Preservation of at least 83% and 85% for CD4⁺ and CD8⁺ T cell responses was found, respectively, regardless of vaccine platform or variants analyzed. By contrast, highly significant decreases were observed for memory B cell and neutralizing antibody recognition of variants. Bioinformatic analyses showed full conservation of 91% and 94% of class II and class I spike epitopes. For Omicron, 72% of class II and 86% of class I epitopes were fully conserved, and 84% and 85% of CD4⁺ and CD8⁺ T cell responses were preserved. In-depth epitope repertoire analysis showed a median of 11 and 10 spike epitopes recognized by CD4⁺ and CD8⁺ T cells from vaccinees. Functional preservation of the majority of the T cell responses may play an important role as a second-level defense against diverse variants.