CATCH-UP vaccines: protocol for a randomized controlled trial using the multiphase optimization strategy (MOST) framework to evaluate education interventions to increase COVID-19 vaccine uptake in Oklahoma

BACKGROUND: Oklahoma’s cumulative COVID-19 incidence is higher in rural than urban counties and higher than the overall US incidence. Furthermore, fewer Oklahomans have received at least one COVID-19 vaccine compared to the US average. Our goal is to conduct a randomized controlled trial using the multiphase optimization strategy (MOST) to test multiple educational interventions to improve uptake of COVID-19 vaccination among underserved populations in Oklahoma. METHODS: Our study uses the preparation and optimization phases of the MOST framework. We conduct focus groups among community partners and community members previously involved in hosting COVID-19 testing events to inform intervention design (preparation). In a randomized clinical trial, we test three interventions to improve vaccination uptake: (1) process improvement (text messages); (2) barrier elicitation and reduction (electronic survey with tailored questions/prompts); and (2) teachable moment messaging (motivational interviewing) in a three-factor fully crossed factorial design (optimization). DISCUSSION: Because of Oklahoma’s higher COVID-19 impact and lower vaccine uptake, identifying community-driven interventions is critical to address vaccine hesitancy. The MOST framework provides an innovative and timely opportunity to efficiently evaluate multiple educational interventions in a single study. TRIAL REGISTRATION: ClinicalTrials.gov: NCT05236270, First Posted: February 11, 2022, Last Update Posted: August 31, 2022.