Although the flu season seems off to a quiet start in the US, warnings from abroad suggest that a new strain may yet shake up the US healthcare system. New data reported in the British Medical Journal showed a significant increase in flu rates in the UK, largely among young adults and school-aged children. The cases are dominated by a new H3N2 strain, which mutated several times over the summer, increasing in severity, according to experts.

Data from Canada, UK, and Japan reveal an H3N2 flu variant that may affect 2025–2026 season.