The recent findings by Shen and colleagues indicating that p53 levels are upregulated upon infection with influenza A virus, leading to IRF9 and Bax upregulation [46], are consistent with previous studies that demonstrated that p53 is important for influenza-induced apoptosis, and thus, cells retaining wt p53 have an enhanced apoptotic response to influenza A infection, which results in impaired viral replication [7]. This evidence concerns the gene IRF9 and influenza.