Panel A and B in Figure S6 showed that both CD4 (p = 0.0188, r = −0.5200) and CD8 (p = 0.0403, r = −0.4304) vaccine responses (represented as FCs after vaccination) were inversely correlated with baseline CD4 or CD8 responses to influenza virus strains. In addition, the humoral vaccine responses measured by FCs of both MN (p = 0.0443, r = −0.4541) and HAI (p = 0.0398, r = −0.4751) titers were also inversely correlated with the baseline influenza antibody levels (Panel C and D). Here, CD4 is linked to influenza.