Clinical and regulatory development strategies for Shigella vaccines intended for children younger than 5 years in low-income and middle-income countries.

Shigellosis causes considerable public health burden, leading to excess deaths as well as acute and chronic consequences, particularly among children living in low-income and middle-income countries (LMICs). Several Shigella vaccine candidates are advancing in clinical trials and offer promise. Although multiple target populations might benefit from a Shigella vaccine, the primary strategic goal of WHO is to accelerate the development and accessibility of safe, effective, and affordable Shigella vaccines that reduce mortality and morbidity in children younger than 5 years living in LMICs. WHO consulted with regulators and policy makers at national, regional, and global levels to evaluate pathways that could accelerate regulatory approval in this priority population. Special consideration was given to surrogate efficacy biomarkers, the role of controlled human infection models, and the establishment of correlates of protection. A field efficacy study in children younger than 5 years in LMICs is needed to ensure introduction in this priority population.