Genomic characteristics of human respiratory syncytial virus from children in China during 2017-2020.

Acute lower respiratory tract infections (ALRTIs) are a leading cause of mortality in young children worldwide due to human respiratory syncytial virus (RSV). The aim of this study was to monitor genetic variations in RSV and provide genomic data support for RSV prevention and control. A total of 105 complete RSV genome sequences were determined during 2017-2020. Phylogenetic analysis showed that all of the RSVA sequences were of genotype ON1, and all of the RSVB sequences were of genotype BA9. Notably, a phylogenetic tree based on the whole genome had more branches than a tree based on the G gene. In comparison to the RSV prototype sequences, 71.43% (50/70) of the ON1 sequences had five amino acid substitutions (T113I, V131N, N178G, H258Q, and H266L) that occurred simultaneously, and 68.57% (24/35) of the BA9 genotype sequences had 12 amino acid substitutions, four of which (A131T, T137I, T288I, and T310I) occurred simultaneously. In the F gene, there were 19 amino acid substitutions, which were mainly located in the antigenic sites Ø, II, V, and VII. Other amino acid substitutions were found in the NS1, NS2, P, SH, and L proteins. No significant evidence of recombination was found in any of the sequences. These findings provide important data that will be useful for prevention, control, and vaccine development against RSV.