GelSite-OAc

GelSite-OAc is an investigational synthetic polysaccharide vaccine candidate developed for the prevention of typhoid fever caused by *Salmonella Typhi*. The vaccine's active ingredient is an O-acetylated high molecular weight polygalacturonic acid derived from *Aloe vera* (GelSite®), which serves as a structural mimic of the natural Vi capsular polysaccharide found on the surface of *Salmonella Typhi*. Unlike traditional Vi polysaccharide vaccines that require complex extraction from wild-type bacterial cultures, GelSite-OAc is produced through the chemical O-acetylation of plant-derived polymers. Preclinical studies have demonstrated that the vaccine is highly immunogenic, provides protection against lethal bacterial challenge, and uniquely exhibits a boosting effect upon re-immunization—a characteristic typically absent in pure polysaccharide vaccines—suggesting potential efficacy in infants and children under two years of age.

Other names

synthetic typhoid Vi polysaccharide vaccineO-acetylated polygalacturonic acid vaccine