FluNexus: A versatile web platform for antigenic prediction and visualization of influenza A viruses

Influenza A viruses pose a major global health threat due to their high mutation rates, broad host ranges, and pandemic potential. Human seasonal influenza is primarily driven by H1 and H3 subtypes, which cause 3–5 million severe cases and 290,000–650,000 respiratory-related deaths annually worldwide. Beyond seasonal outbreaks, avian influenza viruses also present a pandemic threat, particularly the H5 subtype, whose widespread circulation in birds caused serious damage to poultry production, the dairy industry, and public human health. Vaccination is a cornerstone strategy for controlling both seasonal and avian influenza. However, the protective efficacy of vaccines is commonly undermined by rapid antigenic evolution, driven predominantly by mutations in the hemagglutinin subunit 1 (HA1) proteins that confer immune escape. Timely deployment of antigenically matched vaccines can effectively control or even eliminate circulating viruses, as demonstrated by the control of H7N9 in poultry. However, delays in updating vaccines significantly increase outbreak risks, underscoring an urgent need for rapid, high-throughput, and accurate methods to assess viral antigenicity.