Genomic Characterization of Influenza B Victoria Lineage Viruses Circulating in Saudi Arabia During the 2024–2025 Season
TL;DR
These genomes provide regional surveillance data from an underrepresented setting and do not permit inference regarding genomic determinants of disease severity, but larger studies integrating viral genomic, clinical, and host data are needed.
Abstract
Influenza B viruses contribute substantially to global morbidity and mortality, yet genomic data from the Middle East remain limited. We retrospectively performed whole‐genome sequencing of six influenza B virus‐positive residual nasopharyngeal specimens collected at King Abdulaziz Medical City, Riyadh, during the 2024–2025 season, including one fatal pediatric case, and described their genomic features alongside clinical outcomes. All six genomes belonged to the B/Victoria lineage and clustered within V1A.3a.2‐derived subclades circulating globally during 2024–2025. Five genomes, including the fatal pediatric case, were assigned to subclade C.5.6, whereas one non‐fatal case belonged to C.5.7. The Saudi sequences were interspersed among contemporaneous reference strains from Europe, Asia, and North America, without evidence of a distinct local lineage. The fatal isolate did not occupy a distinct phylogenetic position and contained none of the screened virulence‐associated markers, including the neuraminidase N342K substitution. These genomes provide regional surveillance data from an underrepresented setting. Given the small sample size and inclusion of a single fatal case, the findings are descriptive and do not permit inference regarding genomic determinants of disease severity. Larger studies integrating viral genomic, clinical, and host data are needed.