Xiang Xiang Wang

For the 2026–2027 U.S. influenza season, vaccine effectiveness has been forecast by component before the season starts: the topological model gives 40.3%, 56.9% and 47.1% against A(H1N1)pdm09, A(H3N2) and B/Victoria, and the geometric model gives 34.0%, 56.8% and 51.1%. The inputs are 87 hemagglutinin sequences collected in August–September compared with that season's vaccine strains through two mathematical distances, fed into linear regressions fitted on 26 historical season-component observations. These are component point forecasts, not an overall seasonal estimate, with 95% prediction intervals roughly 52–58 percentage points wide, to be checked against final US Flu VE Network estimates.

For the 2026–2027 U.S. influenza season, vaccine effectiveness has been forecast by component before the season starts: the topological model gives 40.3%, 56.9% and 47.1% against A(H1N1)pdm09, A(H3N2) and B/Victoria, and the geometric model gives 34.0%, 56.8% and 51.1%. The inputs are 87 hemagglutinin sequences collected in August–September compared with that season's vaccine strains through two mathematical distances, fed into linear regressions fitted on 26 historical season-component observations. These are component point forecasts, not an overall seasonal estimate, with 95% prediction intervals roughly 52–58 percentage points wide, to be checked against final US Flu VE Network estimates.