Expanded genomic surveillance and characterization of human respiratory syncytial virus infections in Minnesota, USA, 2023-2025

We report the expansion of the genomic surveillance program for human respiratory syncytial virus (HRSV) in Minnesota, USA and summarize analyses of genomes from specimens collected between July 2023 and April 2025. We continued our program into the 2024-2025 respiratory disease surveillance season, generating 2,975 high-quality HRSV genomes. Compared to those from the 2023-2024 seasons, genomes from the 2024-2025 season were collected from greater proportions of patients with HRSV-associated hospitalizations, of older age, and from a broader geographical distribution. Metrics of genetic diversity showed seasonal differences among and between HRSV-A and HRSV-B subgroups. Twenty major subclades and lineage A.D.5.4 were not observed during the 2024-2025 season. We identified 22 amino acid mutations at sites in the fusion protein associated with monoclonal antibody or receptor binding, of which 11 emerged homoplastically. We identified 39 hospitalized patients infected with HRSV strains that carried one of these mutations.