VAX128

VAX128 is a recombinant hemagglutinin (HA) influenza-flagellin fusion vaccine developed to improve safety and immune response against influenza. The vaccine consists of the globular head of the HA1 domain from novel H1N1 genetically fused to flagellin, a Toll-like receptor 5 (TLR5) ligand. Several constructs were evaluated in clinical trials—VAX128A, VAX128B, and VAX128C—differing in how the HA1 was fused to flagellin. The most advanced construct (VAX128C) demonstrated high immunogenicity and favorable safety profiles in phase 1 clinical studies. The mechanism of action involves stimulating an immune response through both presentation of viral antigen (hemagglutinin) and activation of innate immunity via TLR5 signaling by flagellin[1][2][4].