Chapter 30 - Oral Shigella Vaccines

Abstract

Shigella is a major cause of diarrhea and dysentery worldwide; the people who are most affected are young children living in poor areas of the world. The most advanced vaccine approaches employ oral immunization with inactivated or live attenuated organisms or parenteral immunization with O-polysaccharide conjugates and/or bacterial proteins. Oral delivery of whole organisms has been sought to reproduce host immune responses induced after natural infection, which is known to confer protective immunity. The simplicity of manufacturing whole cell vaccines and the practicality of oral vaccination would facilitate implementation in poor areas and allow to reach the most vulnerable groups. Recent global estimates of diarrheal disease have emphasized the burden of Shigella in childhood long-term morbidity and death and have invigorated efforts by public health authorities, scientists, and funding agencies to accelerate vaccine development efforts. This chapter reviews the progress of Shigella vaccine development with a focus on clinically advanced oral vaccine candidates. It summarizes recent information on disease burden, advances in research on animal models of vaccine evaluation, and the current understanding of human immunity resulting from infection and vaccination. It concludes with a discussion of gaps in knowledge, technological advances, and the coordinated efforts to achieve a successful vaccine.