Circulation Patterns of Group A and B Human Respiratory Syncytial Virus Genotypes in 5 Communities in North America

TLDR

Human respiratory syncytial virus (HRSV) is a major cause of serious lower respiratory tract illness in infants, young children, and the elderly. To characterize HRSV circulation patterns, the authors sequenced the C‑terminal region of the G protein gene from 34–53 isolates collected over one epidemic year in five North American communities. Phylogenetic analysis revealed 5–7 genotypes per community, with 1–2 predominant strains, and distinct genotype patterns between communities, showing less diversity within than between communities, which supports community‑based outbreaks and suggests that local factors, possibly immunity from prior strains, determine which genotypes predominate each season.

Abstract

Human respiratory syncytial virus (HRSV) is a major cause of serious lower respiratory tract illness in infants, young children, and the elderly. To characterize the circulation patterns of HRSV strains, nucleotide sequencing of the C-terminal region of the G protein gene was performed on 34–53 isolates obtained from 5 communities during 1 epidemic year, representing distinct geographical locations in North America. Phylogenetic analysis revealed that 5–7 HRSV genotypes, including 1 or 2 predominant strains, circulated in each community. The patterns of genotypes were distinct between communities, and less diversity was seen between strains of the same genotype within than between communities. These findings are consistent with HRSV outbreaks' being community based in nature, although transmission of viruses between communities may occur. Several strains are probably introduced or circulate endemically in communities each year, and local factors—possibly immunity induced by previous years' strains—determine which strains predominate during an HRSV season.