XK and influenza: Currently, the anti-influenza drugs approved by the Federal Drug Administration (FDA) can be divided into two classes: adamantane-based M2 ion channel blockers, which inhibit viral replication by preventing endosome acidification and viral ribonucleoprotein delivery into the cytoplasm, and neuraminidase (NA) inhibitors, which inhibit the release of newly formed virus particles from infected cells (Doll et al., 2017; Ison, 2017).