Evaluating the Impact of Rotavirus Vaccination on Childhood Diarrhea Incidence in Bayelsa State, Nigeria: Achievements, Challenges, and Future Directions (Preprint)

BACKGROUND The introduction of the rotavirus vaccine in Bayelsa State, Nigeria, aimed to combat the high incidence of acute watery diarrhea and associated mortality in children under five. This vaccine initiative responds to the urgent need for effective prevention measures in a region with a history of severe diarrheal disease outbreaks, including cholera. OBJECTIVE This study aims to evaluate the impact of the rotavirus vaccine on the incidence of acute watery diarrhea among children under five in Bayelsa State. Specifically, it seeks to determine the vaccine's effectiveness, assess the coverage and distribution across the state's, local government areas (LGAs) and wards, and analyze the role of Advocacy, Communication, and Social Mobilization (ACSM) in promoting vaccine uptake. METHODS The study employed data from the District Health Information System 2 (DHIS 2) to analyze the incidence of watery diarrhea before and after the vaccine's introduction in January 2023. The coverage and dropout rates of the vaccine were assessed across various LGAs and wards. Facility-level data on acute watery diarrhea cases and vaccination rates were examined to draw conclusions about the vaccine's impact. RESULTS Post-vaccine introduction, there was a notable decline in acute watery diarrhea cases from 424 in December 2022 to 212 in June 2023, indicating the vaccine's effectiveness. However, the disease persists, with the state achieving only 53% coverage of the rotavirus vaccine by June 2023, falling short of the 95% target. The dropout rate was 9%, with disparities in coverage and dropout rates observed across different LGAs. For instance, Brass LGA had a coverage rate of 107%, while Ekeremor LGA had a dropout rate of 23.85%. CONCLUSIONS The rotavirus vaccine introduction in Bayelsa State has significantly reduced acute watery diarrhea incidence among children under five, demonstrating its effectiveness. However, the current vaccine coverage is insufficient to achieve herd immunity, necessitating enhanced ACSM efforts to boost demand and uptake. Recommendations: To improve the impact of the rotavirus vaccine, it is crucial to intensify ACSM activities to raise awareness and demand for vaccination. Strategies should focus on increasing coverage rates to at least 95%, reducing dropout rates, and ensuring equitable vaccine distribution across all LGAs and wards. Continuous monitoring and evaluation should be conducted to track progress and address challenges in vaccine administration. Significance Statement: This study underscores the vital role of the rotavirus vaccine in reducing childhood morbidity and mortality due to diarrheal diseases in Bayelsa State. The findings highlight the importance of robust immunization programs and effective public health strategies in combating infectious diseases in resource-limited settings. Enhanced vaccine coverage and sustained public health efforts are essential to achieving long-term health improvements for vulnerable populations.