CD4 and infection: PBMCs from individuals with vaccination and hybrid immunity (infection plus vaccinated) (Supplementary Table 3) were stimulated with the ancestral whole spike peptide pools or a peptide pool of immunodominant CD4+ and CD8 + T cell epitopes of SARS-CoV-2, and the antigen-specific T cell responses were measured concurrently by conducting AIM, ICS, and IFNγ ELISPOT or IFNγ/IL-2 /TNFα/Granzyme B FluoroSpot (Supplementary Figs. 6, 7).