The role of the enzyme neuraminidase (NA) of influenza in this process has been deeply studied in vitro (Cohen et al., 2013; Yang et al., 2014) but to understand how NA interferes with the mucus cleavage in detail, Vahey and Fletcher (2019) studied with 2-color STORM the organization of hemagglutinin protein (HA) and NA proteins on virions. Here, XK is linked to influenza.