Shigella flexneri-sonnei bivalent conjugate vaccine

The Shigella flexneri-sonnei bivalent conjugate vaccine (ZF0901) is a bivalent conjugate vaccine developed by Chongqing Zhifei Biological Products (through its subsidiary Beijing Zhifei Lvzhu Biopharmaceutical) for the prevention of bacterial dysentery (shigellosis). It targets the two most prevalent species of Shigella, *S. flexneri* (specifically serotype 2a) and *S. sonnei*. The vaccine is composed of O-specific polysaccharides purified and detoxified from the lipopolysaccharide (LPS) of these bacteria, which are covalently linked to a tetanus toxoid carrier protein using an adipic acid dihydrazide linker. This conjugation enhances the immunogenicity of the polysaccharide antigens, particularly in young children, by inducing a T-cell dependent immune response and protective IgG antibodies. It is currently in Phase III clinical development in China and is the first conjugate vaccine developed to prevent infections caused by both *S. flexneri* and *S. sonnei*.

Other names

福氏宋内氏痢疾双价结合疫苗Shigella flexneri-sonnei bivalent conjugate vaccine (tetanus toxoid conjugate)