Molecular Epidemiology of Human Respiratory Syncytial Virus in Iranian ≥60 Years Old Hospitalized Patients with Acute Respiratory Symptoms

Human respiratory syncytial virus (HRSV) is an important cause of acute respiratory infection (ARI) and mortality in ≥60 years old population around the world. The aim of this study was to determine the frequency and circulating genotypes of HRSV in Iranian patients ≥ 60 years old.
In this cross-sectional molecular epidemiology study, we examined the C-terminal located hypervariable domain of G glycoprotein of HRSV in throat swabs from Tehran, Hormozgan, Boushehr, West Azarbayjan, Ghom and Alborz provinces of Iran which were addressed to national influenza center between October 2013 and March 2015. During these two consecutive years, a total of 225 samples collected from patients older than 60 years were tested using RT hemi-nested PCR and sequencing and the acquired sequences were phylogenetically analyzed.
Sixteen out of 225 samples (7.1%) yielded a positive result. Among the positive samples, 13 cases (81%) pertained to antigenic group A and the remaining 3 cases (19%) belonged to group B. Three genotypes including GA1, GA2 and BA9 were identified in the first year of survey whereas during the second year, only GA1 and GA2 genotypes were detected.
Our study indicates that HRSV genotypes from both A and B antigenic groups which were discovered in pediatric population previously, are circulating among Iranian ≥60 years old population.