Optimizing the Use of Oral Cholera Vaccine for Enhanced Impact: A Randomized Controlled Trial and Observational Study to Inform Vaccination Strategies in Kenya

Through a comprehensive approach that includes a randomized controlled trial, immunological analysis, and case data analysis in Kenya, our consortium will provide valuable knowledge and new understanding to maximize the effectiveness of oral cholera vaccine usage. In a trial, we will compare the immunogenicity of three distinct vaccine dosing schedules: the manufacturer-recommended two- week schedule, a three-month schedule, and a twelve-month schedule. We will enroll participants from different age groups, including children under five years old, to compare age-specific responses accurately. Furthermore, a subset of participants will undergo in-depth immunological analyses to investigate whether extended interval dosing enhances the production of vaccine-induced memory B cells and antibody-secreting cells, which are more indicative of long-term protective immunity compared to measuring circulating antibody levels alone. Additionally, we will assess the overall impact of the planned preventive vaccination campaign by the Kenyan government. This assessment will analyze data from different sub-counties in Nairobi on vaccination coverage, case trends, and changes within and between various geographic areas. By combining the trial results and the analysis of case data, we aim to provide critical evidence and relevant insights to inform cholera vaccination strategies, optimize vaccine utilization, and strengthen cholera control efforts in Kenya and beyond.