Promising directions for vaccine development to prevent shigellosis

Abstract

Shigellosis (bacterial dysentery) is an acute infectious disease caused by Shigella spp., members of the Enterobacteriaceae family. The disease has the highest mortality rate amongst bacterial enteric infections. A considerable proportion of Shigella infections occur in children under the age of five. In 2017, WHO included Shigella spp. strains into the list of “priority pathogens” that are resistant to most antibiotics and pose a threat to global public health. This provided a stimulus for the development of new antibiotics to treat shigellosis. Apart from the creation of new antimicrobial therapies for Shigella infections, an important role in fighting against shigellosis belongs to the preventative measures set out in WHO’s Immunisation Agenda 2030. These include sanitation, hygiene, consumption of clean water, and vaccination. The development of Shigella vaccines has been a priority of the WHO programme for more than 20 years. The aim of the study was to analyse promising approaches to Shigella vaccine development. According to the analysis of literature, only one vaccine against shigellosis has been approved so far—Shigellvac, the Russian polysaccharide dysentery vaccine against Shigella sonnei. This study covers a number of vaccine candidates (whole-cell, polysaccharide, polysaccharide conjugate, protein antigen-based vaccines, etc.) that are at different stages of clinical trials. The importance of researching combination (multivalent) vaccines against Shigellа spp. and other enteric pathogens is noted. However, the authors consider subunit vaccines based on Ipa proteins, providing broad cross-protection against Shigellа spp., and conjugate polyvalent vaccines for children under 5 the most promising for further development.