Moreover, Ad vector-based influenza vaccines expressing hemagglutinin (HA) [46,47,48], neuraminidase (NA) [49,50], NP [51,52], matrix protein 1 (M1) [53,54,55], or immunogenic domains or epitopes [56,57] have been developed, which showed great potential in providing significant protection against influenza viruses in experimental animals or human clinical trials. Here, XK is linked to influenza.