# Efforts to Enhance Recruitment and Engagement of Caregivers from Medically Underserved Communities in a Randomized Controlled Trial of a Vaccine Promotion App

## TL;DR

This study shows how a vaccine promotion app trial successfully recruited caregivers from medically underserved communities across 15 states.

## Contribution

The paper presents a successful recruitment strategy for diverse populations in a large-scale vaccine communication trial.

## Key findings

- The trial recruited a higher proportion of Hispanic and Black participants compared to national averages.
- 34.3% of enrolled participants lived in rural areas, reflecting geographic diversity.
- High survey completion rates (70.6% baseline, 82.4% final) indicate strong engagement.

## Abstract

Over 15 million children in the United States have been infected with COVID-19; nearly 2,000 have died. Approval of COVID-19 vaccines for children enabled reductions in disease severity and mortality. Disparities in vaccine adoption exist along racial, ethnic, and rural–urban lines, with lower uptake among medically underserved populations (e.g. Black, non-Hispanic White rural populations) compared to urban White populations. This study examined efforts to recruit and engage a diverse cohort as part of a vaccine communication randomized trial conducted across 15 states and compared demographic characteristics of the enrolled cohort to the broader US population. To enhance recruitment of diverse populations, eligible clinics had to serve a significant proportion of medically underserved individuals based on race, ethnicity, or geographic location. Coordinators used both traditional (in-person daily clinic schedule review) and retrospective (EHR and billing data review) recruitment methods adapted to enrich engagement with focus populations. Demographic characteristics were compared to national statistics obtained from the CDC’s Household Pulse Survey. In total, 2999 parents/caregivers were screened; 725 were randomized (24.1%). Comparing enrolled subjects to the demographics of participating states, 17.3% vs 9.8% self-identified as Hispanic, 39.6% vs 13.0% as Black. Additionally, 34.3% self-described as living in a rural area. Of the 725 randomized, 512 (70.6%) completed the baseline survey. Of these 512, 422 (82.4%) also completed the final survey of the 24-week study. This analysis demonstrates the Institutional Development Award States Pediatric Clinical Trials Network can successfully recruit and engage populations from diverse and underrepresented populations in research.