Global Implications for COVID-19 Vaccine Series Completion: Insights from Real-World Data from the United States

This retrospective cohort analysis leveraged vaccination data for BNT162b2, mRNA-1273, and Ad26.COV2.S in the United States from the Komodo Healthcare Map database, the TriNetX Dataworks USA Network, and Cerner Real-World EHR (electronic health record) Data to evaluate rates of adherence to and completion of COVID-19 vaccination series (November 2020 through June 2021). Individuals were indexed on the date they received the first dose of a COVID-19 vaccine, with an adherence follow-up window of 42 days. Adherence/completion rates were calculated in the overall cohort of each database and by month of initiation and stratified by age, race/ethnicity, and urban/rural status. Overall adherence and completion to 2-dose COVID-19 mRNA vaccine schedules ranged from 79.4% to 87.4% and 81.0% to 89.2%, respectively. In TriNetX and Cerner, mRNA-1273 recipients were generally less adherent compared with BNT162b2 across sociodemographic groups. In Komodo, rates of adherence/completion between mRNA-1273 and BNT162b2 were similar. Adherence/completion were generally lower in younger (<65 years) versus older recipients (≥65 years), particularly for mRNA-1273. No other sociodemographic-based gaps in vaccine adherence/completion were identified. These data demonstrate high but incomplete adherence to/completion of multidose COVID-19 vaccines during initial vaccine rollout in the United States. Multidose schedules may contribute to challenges associated with successful global vaccination.