Shigella is a gram-negative bacteria responsible for an estimated 60,000 deaths each year in children under 5. In low and middle-income countries, nearly one-third of children experience at least an episode of Shigella-attributable diarrhea during their first 2 years of life. Shigella infection is also associated with linear growth failure, a marker of vulnerability to childhood infection, decreased vaccine efficacy, and lifelong morbidity. The morbidity and mortality attributed to Shigella combined with the rise in antimicrobial-resistant Shigella infections make this a priority pathogen to prevent.
Several promising Shigella vaccines are in development and Phase IIb/III clinical trials in the target population of children living in low- and middle-income countries are slated to begin as early as 2024. Eventual trials will require a consortium of LMIC sites in settings with a high incidence of Shigella-attributed diarrhea, specifically of vaccine-preventable Shigella serotypes; a demonstrated track record of following Good Clinical Practice (GCP) standards; high participant retention; and the laboratory capacity to confirm Shigella infection. Such preparatory efforts will ensure costly clinical trials do not fail due to insufficient statistical power, high loss to follow-up, or substantial heterogeneity in the diagnostic performance of microbiologic methods for Shigella confirmation.