Fig. 4. Cellular immune memory subpopulations to Omicron.
Pooled peptide spike-specific IFNγ CD8+ and CD4+ central memory (CD45RA−CD27+) and effector memory (CD45RA−CD27−) T cell responses by intracellular cytokine staining assays at months 1 and 8 following final vaccination with Ad26.COV2.S (n = 20). Responses were measured against the SARS-CoV-2 WA1/2020, B.1.617.2 (Delta) and B.1.1.529 (Omicron) variants. Medians (red bars) are depicted and numerically shown.