This is a site-level block-randomized trial. The study population is Custodial parents/caregivers with ≥1 child eligible for COVID-19 vaccination who has not yet received the vaccine at the time of study enrollment.~The primary objective is to determine the effect of a parent-facing, vaccination decision-making mobile health (mHealth) tool on children's COVID-19 vaccine series completion. The endpoint of this objective is the proportion of children who complete COVID-19 vaccination, as verified in state, clinic, or participant-held records.~Secondary Objective 1 is to determine the effect of a parent-facing, vaccination decision-making mHealth tool on children's COVID-19 vaccine series initiation. The endpoint of this objective is the proportion of children who receive ≥1 dose of the COVID-19 vaccination series, as verified in state, clinic, or participant-held records~Secondary Objective 2 is to determine the effect of a parent-facing, vaccination decision-making mHealth tool on parental attitude toward pediatric COVID-19 vaccination. The endpoint of this objective is the change in enrolled parent/caregiver domain scores from baseline to week 16 on the modified World Health Organization (WHO) Strategic Advisory Group of Experts on Immunization (SAGE) Vaccine Hesitancy Scale adapted for the COVID-19 Vaccine.~Enrolling sites will recruit participants. These sites will collaborate with outpatient practices within Environmental influences on Child Health Outcomes (ECHO) Institutional Development Award (IDeA) States Pediatric Clinical Trials Network (ISPCTN) states that provide primary care services to children (<18 years old). Sites will serve a population base of at least 40% Medicaid/uninsured children, <60% non-Hispanic White children, or >40% of families residing in rural communities. Sites are encouraged, but not required, to have a high Spanish-speaking population.~Study interventions are a Vaccine Uptake App and General Health App. The Vaccine Uptake App will include 24-week (8 weeks with weekly push notifications; 2 monthly push notifications for 2 months [1 notification per month]; 8 weeks without) exposure to a mobile phone application (app) designed to improve parental knowledge, attitudes, and self-efficacy regarding pediatric COVID-19 vaccination. The app will address logistical and motivational barriers to pediatric COVID-19 vaccination. Participants will also receive eight weekly nudges and 1 monthly nudge for 2 months (cues to action) regarding vaccinating their child that will be sent to participants via push notifications to their mobile devices. Through branching logic, users will access content tailored to their COVID-19 vaccine knowledge and confidence gaps, locality, degree of rural-urban primary residence, primary language (English/Spanish), race/ethnicity, and child's age.~The General Health App will include 24-week (8 weeks with weekly push notifications; 2 monthly push notifications for 2 months [1 notification per month]; 8 weeks without) exposure to a mobile phone app designed to provide information on general pediatric health and infection prevention and mitigation strategies based on recommendations from the American Academy of Pediatrics (AAP) and the Centers for Disease Control and Prevention (CDC). Nudges regarding these topics will be sent to participants via push notifications to their mobile devices.~The study duration is 24 months (6 months study start-up; up to 8 months rolling enrollment; 7 months final participants' completion; 3 months analysis). Participant duration is 27 weeks.
This study will determine the effectiveness of a vaccine communication mobile health app on parental decisions to vaccinate their children against coronavirus disease 2019 (COVID-19).~The hypothesis is that unvaccinated children of caregivers assigned to the Vaccine Uptake app will be more likely to achieve COVID-19 vaccine series completion than those children whose caregivers are assigned to the General Health app.