OFFLU Avian Influenza Matching (AIM) Technical Report - September 2025

This document provides the September 2025 OFFLU Avian Influenza Matching (AIM) technical report, summarising standardised HI assays and antigenic cartography to assess vaccine–virus match for contemporary H5Nx (notably clade 2.3.4.4b), presenting phylogenetic context, antigenic distance results (showing within-clade vaccines generally remain suitable while older/out-of-clade seeds show limited cross-reactivity), and outlining guidance and next steps for surveillance, reagent panels, and vaccine strain selection.