An overview of respiratory syncytial virus infections in Saudi Arabia.

Respiratory syncytial virus (RSV) is a major pathogen of acute respiratory tract infection (ARI) in different geographical regions including Saudi Arabia. Numerous hospital-based investigations have revealed the RSV prevalence between 0.2-54% in the paediatric population with ARI/ALRI from Saudi Arabia during 1991-2015. Maximum RSV infections occurred in children less than 1 year of age (51-97%) and male children (51-69%) were more commonly affected than females (31-49%). RSV infections are reported mostly during winter season suggesting seasonal distribution of the virus. Other respiratory viruses reported from this region are adenovirus, influenza, parainfluenza, human metapneumovirus and rhinovirus including many mixed infections. A few studies have reported the phylogenetic analysis of the circulating strains of RSV. These studies have revealed that circulating group A-RSV Saudi strains belonged to NA1 and ON1 genotypes and group B-RSV viruses clustered in the BA genotype. Molecular characterization of the Saudi strains was further carried out by mutational, selection pressure and glycosylation site analyses. We have compiled all the eighteen studies of RSV infection from Saudi Arabia in the form of this review and concluded that detailed comprehensive surveillance of RSV and other viruses in community and hospital settings is required. Information on the molecular characterization of currently circulating strains of RSV will contribute towards better understanding of the epidemiology and evolutionary dynamics of this viral pathogen. Moreover, the determination of the genetic composition of circulating RSV strains will be important during evaluation of initial vaccine trials.