Mobile Vaccine Uptake (MoVeUP): a randomized effectiveness trial for a vaccine communication app

COVID-19 vaccine uptake among children remains low. Bundling multiple strategies into a mobile health (mHealth) application (app) may be effective in promoting vaccine uptake. We aimed to determine the effectiveness of a caregiver-facing mHealth app on pediatric COVID-19 vaccine uptake.

Caregivers of a child unvaccinated for COVID-19 were recruited from 29 clinics in 15 states. Caregivers were randomized to either a COVID-19 vaccine communication (Vup) or a general health education (GenH) app. Caregivers self-reported (with verification) their child's COVID-19 vaccinations over a 24-week study period. Mixed-effect Poisson regression models were run adjusting for clinic and stratified by child age and rurality.

From 15Jul22-14Feb23, 727(32% rural, 50% white) caregivers of 1205 unvaccinated children were enrolled. 22(3.7%) children of caregivers randomized to VUp compared to 25(3.6%) and 7(1.1%) children of caregivers randomized to GenH initiated COVID-19 vaccination (unadjusted relative risk (uRR): 0.85(95% CI:0.49-1.50). 13(2.2%) Vup versus 7(1.1%) GenH completed (uRR: 1.80(95%CI:0.72-4.49)). Among rural children, the uRR of vaccine series completion was 6.22(95%CI:1.38-28.03). Adjusted models showed similar effect sizes.

Overall low vaccination uptake in this diverse cohort limited the power to detect an effect. Future studies should examine the utility of mHealth apps on other vaccinations, particularly in rural populations.