Vi-rEPA

Vi-rEPA is an investigational typhoid conjugate vaccine developed by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). The vaccine is composed of 25 μg of the Vi capsular polysaccharide from *Salmonella typhi* covalently linked to 25 μg of recombinant exoprotein A (rEPA) from *Pseudomonas aeruginosa*, which serves as a carrier protein. This conjugation converts the Vi polysaccharide from a T-cell independent antigen into a T-cell dependent immunogen, significantly enhancing its immunogenicity and efficacy in young children and infants. Clinical trials in Vietnam demonstrated that Vi-rEPA has a 91.5% efficacy rate in preventing blood culture-confirmed typhoid fever in children aged 2 to 5 years, with protection lasting at least four years. It has also been evaluated for safety and compatibility when co-administered with routine infant vaccinations such as DTP. Despite its high efficacy, the vaccine is not currently commercially available.

Other names

Vi-rEPA conjugate vaccineVi-rEPA typhoid conjugate vaccineTyphoid Vi-rEPA vaccine