With this background in mind, in the present study, we aimed to perform molecular and phylogenetic analyses of NA genes from 2009 pandemic H1N1 influenza viruses (identified in 2009–2010, 2010–2011, and 2012–2013) in patients referring to Masih Daneshvari Hospital, a specialized and referral center for lung diseases in Tehran, Iran. Here, XK is linked to lung disorder.