Phylogenetic Comparison of Influenza VirusIsolates from Three Medical Centers in Tehranwith the Vaccine Strains during 2008-2009

Background: influenza virus is a major infectious pathogen of therespiratory system causing a high degree of morbidity and mortalityannually. the worldwide vaccines are decided and producedannually by world health organization and licensed companiesbased on the samples collected from all over the world. the aim ofthis study was to determine phylogenecity and heterogenecity ofthe circulating influenza isolates during 2008-2009 outbreaks intehran, compare them with the vaccine strains that were recommendedby who for the same period.methods: nasopharyngeal swabs (n=142) were collectedfrom patients with influenza and influenza-like illness. typingand subtyping of the isolates were performed using multiplexrt-pcr and phylogenetic analysis was carried out for hemagglutiningenes of the isolates.results: fifty out of 142 samples were positive for influenzaa virus, and no influenza b virus was detected. phylogeneticanalyses revealed that the a/h1n1 isolates were relatedclosely to a/brisbane/59/2007, and the a/h3n2 isolates wereclose to a/brisbane/10/2007 vaccine strains.conclusion: the findings of the present study demonstratethat the a/h1n1 was the predominant subtype of human influenzavirus among the patients studied in tehran during2008-2009 winter seasons. in addition, some amino acid variationwas found in tehran/2008/h1n1 isolates from the 2008-2009 vaccine strain, but the h3n2 isolates showed higher geneticresemblance to the vaccine strain