Predictors of initiation and completion of Shingrix vaccination in immunocompetent adults newly eligible for vaccination from 2018–2024

The Shingrix vaccine has been recommended for immunocompetent adults aged ≥50 y since October 2017. It is important to assess recent trends and predictors of Shingrix vaccination among those newly eligible to evaluate acceptability, desirability, and uptake of the vaccine. In this retrospective cohort study, we used electronic health record data with linked medical and pharmacy claims data from Truveta. Immunocompetent adults turning 50 between 2018 and 2024 with at least 1 y of continuous enrollment after their 50th birthday were included. We estimated the cumulative incidence of vaccination by eligibility year and assessed series completion at 6 and 12 m. Multivariable logistic regression identified predictors of initiation and series completion. Among 153,899 adults (57.0% female; 62.2% White), 9.9% received ≥1 Shingrix dose within 1 y of eligibility. One-year uptake increased from 2.6% (2018 cohort) to 14.0% (2024 cohort). Three-year uptake reached 27.5% among those eligible in 2022. Among initiators within the first year of eligibility, 62.6% completed the series within 6 m and 74.5% within 12 m. Influenza vaccination during a person's 50th y was the strongest non time-based predictor of Shingrix vaccination (odds ratio 1.96, 95% CI 1.88-2.03). Women and Asian adults had higher odds of initiation, whereas Black or African American adults, Medicaid/CHIP enrollees, rural residents, and those with cardiovascular disease had lower odds. Shingrix uptake among newly eligible adults has increased rapidly since 2018. Persistent sociodemographic disparities highlight the need for targeted strategies to improve equitable vaccine uptake.