However, the polyfunctional cytokine profiles of CD4+ T cell (p = 0.0097, p = 0.037 for BA.1 and BA.4/5, respectively; Figure 5D) and CD8+ T cell (p = 0.0001, p = 0.010, respectively; Figure 5E) responses were lower in inactivated vaccine-healthy individuals than those in breakthrough infection individuals. Here, CD4 is linked to infection.