The Johns Hopkins Center for Immunization Research is looking for healthy volunteers to participate in an inpatient shigella vaccine study that has both an outpatient and inpatient portion. The purpose of this study is to find out if an experimental bioconjugate vaccine targeting four strains of shigella, called Shigella4V2, protects people from getting sick from shigella. If you are between the ages of 18 and 50, you may be eligible to participate.