Influenza-specific cytotoxic CD4
T-cell responses to vaccination in the per protocol immunogenicity cohort. Box and whisker plots describing the frequency of CD4+ or CD8+ T cells specific for the three (pooled) influenza vaccine strains and induced to express Granzyme B and IFN-γ and/or IL-2 (Spanish subjects only). For the TIV/AS03(≥65), TIV(≥65) and TIV(18–40) groups, N = 30–32, 35–36 and 24–25, respectively. The whiskers extend to the lowest (Min) and highest (Max) values; the box extends to the 1st quartile (Q1) and 3rd quartiles (Q3) in which the median is marked by a horizontal line.