In the combined group, IQGAP2 rs2455230 GC + CC genotype was also correlated with a lower risk of low responsiveness to influenza vaccination compared with the GG genotype (P = 8.90E-04, OR = 0.535, 95%CI = 0.370–0.774), but the difference was not statistically significant in group 2 (P = 0.008). This evidence concerns the gene IQGAP2 and influenza.