Figure 6.

AZD1222 vaccinees possess an enriched SARS-CoV-2 spike-specific T-cell response upon symptomatic SARS-CoV-2 infection compared with placebo recipients. T-cell responses from vaccinees and placebo recipients were assessed following stimulation of PBMCs with SARS-CoV-2 spike peptide pools. Frequencies of SARS-CoV-2 spike protein-specific CD4+ T cells (A) expressing CD154, interferon gamma (IFNγ), IL-2, and tumor necrosis factor alpha (TNFα), or any combination of all four (Any Response), and CD8+ T cells (B) expressing IFNγ, IL-2, and TNFα, or any combination of all three (Any Response) are shown. Illness visit day 1 cytokine profiles and frequencies of (C) CD4+ and (D) CD8+ T cell populations upon breakthrough infection in vaccinees and placebo recipients. Spike-specific CD4+ (E) and CD8+ (F) T-cell frequencies (Any Response) from participants at ILL-D1 and ILL-D14 are shown. Bars indicate median values within each group. Frequencies of spike-specific CD4+ (G) and CD8+ (H) T-cells (Any Response) against ancestral SARS-COV-2 and Omicron BA.1 variant spike proteins from vaccinee and placebo recipient “responders” at illness visit day 1. In the box and whisker plots the horizontal line represents median, boxes represent IQR, whiskers extend to minimum and maximum, and each symbol represents a participant. Dotted line indicates “responder” threshold. Statistical evidence between groups were determined by two-tailed Mann-Whitney tests. Not significant (NS), P>0.05; *P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001. An. = Ancestral; O = Omicron.