Effectiveness of an Education Toolkit Delivered by Soap Operas Among Communities Living in Extreme Poverty in Improving Vaccination Confidence in the Philippines: Protocol for a Cluster Randomized Controlled Trial.

BACKGROUND: Measles and polio pose significant public health challenges globally, particularly in low-resource settings such as the Philippines, where vaccine coverage falls short of the World Health Organization's (WHO's) targets, with hard-to-reach populations contributing to the "last mile." This research addresses the "last mile" challenge in routine immunization efforts by bridging the vaccination gap in marginalized populations. OBJECTIVE: We describe the implementation of a cluster randomized controlled trial to evaluate the impact of an education toolkit aimed at improving confidence in measles and polio vaccines among communities living in extreme poverty in the Philippines. METHODS: Developed with local stakeholders, our intervention consists of a 10-minute video and vaccination reminders delivered by health trainers. It is embedded within the Soap Opera Trial, a large cluster randomized controlled trial conducted by the International Care Ministries that evaluates a 15-episode soap opera series combining drama with aspirational messages on hope, self-worth, and education, aimed at improving participants' knowledge and practices in health, hygiene, nutrition, and livelihood. A total of 180 communities with 5400 participants will be randomly assigned to the intervention and control arms. By leveraging an existing community-based education program on health and livelihood run by our local partner, the proposed intervention will be delivered to participants in the intervention arm of the existing program, while those in the control arm will receive standard participatory adult learning sessions on health education. The primary outcome is the first-dose measles-containing vaccine coverage among participants' children aged 1 year. Secondary outcomes include the 2-dose measles-containing vaccine coverage among children aged 2 to 6 years, polio vaccination coverage among children aged 1 year, and participants' knowledge of measles and polio vaccines. The absolute differences in these outcomes between the intervention and control arms will be estimated using generalized estimating equations while adjusting for baseline levels and covariates. In addition, we will conduct a process evaluation. RESULTS: Between January 31 and February 29, 2024, we recruited 66.9% (3613/5400) of the participants for the trial. Data collection is ongoing at the time of manuscript submission. CONCLUSIONS: Findings from this trial will provide critical insights into effective strategies for enhancing vaccine confidence and uptake in marginalized populations. By leveraging community-based approaches and local partnerships, this study aims to improve public health responses to vaccine-preventable diseases and contribute to global efforts to eradicate measles and polio. Furthermore, the findings will inform scalable interventions that can be adapted to similar contexts, potentially reducing health disparities and advancing global health equity. TRIAL REGISTRATION: ClinicalTrials.gov NCT06218368; https://clinicaltrials.gov/study/NCT06218368. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/77022.