Figure 3.

T cell proliferation to SARS-CoV-2 at 6 months after the primary vaccine course of two doses of BNT162b2 or AZD1222

T cell proliferation to SARS-CoV-2 peptide pools was assessed by flow cytometry in PBMCs from 73 participants who had received either BNT162b2 with a short or long vaccine dosing interval or AZD1222 vaccine and were either naive or were previously infected (either at baseline or during the course of the study).

(A) Relative frequency of CD4⁺ and CD8⁺ T cells proliferating to individual peptide pools spike S1, spike S2, membrane (M), and N protein in naive (n = 39) and hybrid immunity (n = 34) individuals. Gray color, missing value.

(B–E) (B and D) Proliferation to S1 and S2 and (C and E) M and N protein in CD4⁺ (B and C) and CD8⁺ (D and E) T cells are shown across the three vaccine regimens separated by exposure status (naive versus hybrid immunity). Individual data points and median with IQR are displayed for naive short, n = 16; naive long, n = 15; naive AZ, n = 8; hybrid immunity short, n = 11; hybrid immunity long, n = 12; hybrid immunity AZ, n = 11. Comparisons between naive and hybrid immunity within each vaccine regimen were performed using the Mann-Whitney test, and comparisons between the three vaccine regimens within the naive and previously infected groups was performed using the Kruskal-Wallis test and Dunn’s multiple comparisons correction. Two-tailed p values are shown only for statistically significant comparisons (p ≤ 0.05). Fold change between medians of two groups are shown in brackets next to or under p value. (Fold change is not shown for those comparisons where there was no proliferation detected in one of the groups.) Gray circles, naive individuals; red circles, participants with hybrid immunity. Central horizontal bars represent the median, and error bars represent the IQR.