WRSs3

WRSs3 is a live, attenuated oral vaccine candidate developed to prevent infection by Shigella sonnei, a major cause of bacillary dysentery worldwide. It is engineered by deleting the VirG/IcsA gene, which impairs bacterial spread within the colonic epithelium and thus attenuates virulence. WRSs3 is designed to elicit both systemic and mucosal immune responses, including serum bactericidal antibody (SBA) activity and opsonophagocytic killing antibody (OPKA) activity. Clinical studies have shown that a single oral dose induces robust functional IgG- and IgA-mediated anti-microbial immunity in both serum and fecal samples, with peak responses observed around days 10–14 post-vaccination. The vaccine has demonstrated safety and immunogenicity across a range of doses in healthy adults[1][2][3][5][6].