An increase in Neu5Ac-α2-6 binding has been associated with Lys189Arg (present in both Hubei10 and Egypt10) [48], and the deletion of Leu129 coupled with the substitution Ile151Thr (present in Egypt10), has been shown to increase viral binding to Neu5Ac-α2-6-Gal and infection in the airway epithelia of humans [3]. Here, IGKV6-21 is linked to infection.