Furthermore, co-occurring mutations in the HA or NA proteins, including H122Q, A127T, P144L, N150K, G181E, S194D, and K200R in HA and D53N, N59S, and G233E in NA were detected in 56.3% (18/32) of the patients with influenza-B-associated pneumonia. This evidence concerns the gene XK and susceptibility to pneumonia measurement.