Exploring Shigella vaccine priorities and preferences: Results from a mixed-methods study in low- and middle-income settings

BACKGROUND: Shigella is the leading bacterial cause of diarrheal mortality in children and can cause long-term effects on growth and development. No licensed Shigella vaccines currently exist but several promising candidates are in development and could be available in the next five years. Despite Shigella being a well-known public health target of the World Health Organization for decades, given current burden estimates and competing preventable disease priorities in low-income settings, whether the availability of an effective Shigella vaccine will lead to its prioritization and widespread introduction among countries at highest risk is unknown. METHODS: We conducted a mixed-methods study of national stakeholders and healthcare providers in five countries in Asia and Africa and regional stakeholders in the Pan American Health Organization to identify preferences and priorities for forthcoming Shigella vaccines. RESULTS: In our study of 89 individuals, diarrhea was the most frequently mentioned serious health concern for children under five years. Antimicrobial resistance (AMR) was more often considered very concerning than diarrhea or stunting. Shigella awareness was high but not considered a serious health concern by most stakeholders. Most participants were willing to consider adding a new vaccine to the routine immunization schedule but expressed reservations about a Shigella vaccine because of lower perceived burden relative to other preventable diseases and an already crowded schedule; interest was highest among national stakeholders in countries receiving more financial support for immunization. The priority of a Shigella vaccine rose when participants considered vaccine impacts on reducing stunting and AMR. Participants strongly preferred oral and combination vaccines compared to injectable and a single-antigen presentations, citing greater perceived community acceptability. CONCLUSIONS: This study provides a critical opportunity to hear directly from country and regional stakeholders about health priorities and preferences around new vaccines. These findings should inform ongoing Shigella vaccine development efforts and eventual vaccine introduction and implementation planning.