IFITM3 and influenza: Regarding the different viral subtype or lineage of IVI, we found that IFITM3 rs12252 CC genotype was associated with severe infection in total influenza A, influenza A (H3N2), total influenza B and B (Yamagata) virus-infected cases (p < 0.001, p < 0.001, p < 0.01, and p < 0.01, with crude OR of 4.83, 4.83, 3.74, and 3.76, respectively).