Molecular evolution of respiratory syncytial virus subgroup A collected in north Viet Nam between 2017-2020

Abstract The respiratory syncytial virus is a major cause of acute respiratory tract infection in young children. However, molecular characteristics analysis was not as much of its’ burden, especially in developing countries as well as Viet Nam. Therefore, we performed molecular evolutionary analyses of the G gene of RSV-A sequences which were collected from pediatric severe acute respiratory infection patients in north Viet Nam from 2017–2020. The Bayesian Markov Chain Monte Carlo method was used to conduct phylogenetic analyses and a time scale for evolution. We also calculated population dynamics, estimated the natural selection pressure and potential N-glycosylation sites. The results indicated the majority of study sequences were classified into the ON1 genotype. There were three strains belonging to the non-ON1 genotype with p-distance = 0.048. Besides, even though most of the Vietnamese sequences were identified as ON1 genotype, all of them had no 72-nucleotide duplication in the second hypervariable region of the G gene. The molecular evolutionary rate of the RSV-A G gene in northern Viet Nam was estimated to be 1.32 × 10 − 3 substitutions/site/year. Each year, the shifts of the N-glycosylation pattern within the G gene of Vietnamese sequences were observed. Moreover, five amino acid substitution sites were related to positive selection pressure. These results were the first report of the molecular evolution of the RSV-A G gene detected in Viet Nam after 2015.