# Improving uptake of pediatric vaccines through religious conferences and mobile vaccine clinics in Aceh, Indonesia (TABRIE): study protocol for a stepped wedge cluster randomized controlled trial

## TL;DR

This study tests whether religious conferences and mobile clinics can improve childhood vaccination rates and parental attitudes in Aceh, Indonesia.

## Contribution

The study introduces a novel approach combining religious engagement and mobile clinics to address vaccine hesitancy in a conservative region.

## Key findings

- The stepped wedge design will assess the impact of religious and mobile interventions on vaccination coverage.
- Baseline and follow-up surveys will measure changes in parental attitudes and access barriers.
- Results may inform community-centered solutions to vaccine hesitancy in low-resource settings.

## Abstract

Despite advancements in child immunization, inadequate immunization rates in low- and middle-income countries persist due to inadequate health infrastructure, challenges in vaccine supply and distribution, insufficient healthcare provider training, and low levels of community trust in vaccines. Aceh, a religiously conservative province in Indonesia, has low pediatric vaccination coverage and exemplifies the need for innovative vaccine delivery models. Evidence suggests interventions should target both logistical barriers (e.g., distance or clinic wait times) and societal factors, including misinformation, that contribute towards vaccine hesitancy.

The trial “TABRIE” will measure the impact of two strategies on children’s vaccination rates and parental attitudes towards vaccines in Banda Aceh and Aceh Besar, Indonesia, compared to current outreach strategies. The two strategies being tested are (a) an informational conference with religious leaders who work in specific clinics and (b) a mobile vaccine clinic staffed with community health workers conducting a variety of outreach events. We will execute a stepped wedge cluster randomized design with baseline measures and a cross-sectional sampling structure. Twelve districts (Kecamatan) will be randomized into one of the two strategies. In year 1, three districts from each strategy will implement the intervention, with the other three districts implementing the strategy in the second year. We will conduct cross-sectional surveys in September 2023 (baseline), September 2024 (year 1), and September 2025 (year 2). The primary outcome is the proportion of fully vaccinated children aged 1–5 years for bacillus Calmette-Guérin (BCG), diphtheria-tetanus-pertussis (DTP), polio, and measles. Secondary outcomes include the proportion of children aged 1–5 years with at least one dose of DTP and measles vaccines, the proportion of vaccine-hesitant parents, social norms surrounding vaccination, parental trust in community health workers to administer vaccines, the proportion of parents experiencing distance barriers to vaccination, the proportion of parents reporting that their religious leader encourages vaccination, and the proportion of parents receiving vaccination information from their religious leader.

This study will conduct a stepped wedge cluster randomized trial to separately estimate the effects of religious conferences and mobile vaccine clinics on pediatric vaccination rates and parental attitudes towards vaccination. It will offer a novel paradigm in vaccination delivery by inserting vaccination from clinics into social spaces that provide alternative, community-centered policy solutions to vaccine hesitancy.

ClinicalTrials.gov NCT06160999. Registered on December 14, 2023.