mRNA vaccination boosts T cell memory in COVID-19 recovered individual

This study evaluated how prior SARS-CoV-2 infection influences T cell responses elicited by mRNA vaccination. Pre-existing spike-specific memory predicted the magnitude and clonal expansion of CD8+ T cell responses, with the most pronounced boosting observed in individuals carrying HLA-A03:01. In four A03:01 vaccine recipients profiled longitudinally at the single-cell level, progressive exposures through vaccination repeatedly reactivated infection-primed CD8+ T cells and appeared to drive differentiation of responding clones toward a TEMRA-like phenotype while retaining antiviral effector function.