Biology and Life Sciences #2026 flu season forecast

As December 2025 draws to a close, the SARS-CoV-2 XFG variant—nicknamed "Stratus"—has surged to dominate 69% of U.S. cases, driven by seven key mutations enabling immune evasion. This real-time analysis maps the variant's spread, symptoms, and vaccine effectiveness, offering actionable insights for the 2026 season.

As 2025 winds down, a new H3N2 variant—subclade K—armed with seven key mutations is igniting fears of a severe 2026 flu season. This real-time tracking guide breaks down the strain's rise, global spread, vaccine challenges, and protective strategies to stay ahead of the surge.