CD4 and infection: To gain a clearer understanding of the relationship between S‐specific CD4 T cell subsets and their functions in conjunction with various other parameters, a Spearman' correlation matrix was conducted using key T‐cell subsets from the flow cytometry dataset, along with time post‐infection, age, IgG, and neutralising titres for both early convalescence (T1) and 11–14 months post infection (T4) (Figure 7a).