OBJECTIVES: Increase understanding of COVID-19 vaccination uptake at Walgreens pharmacies and vaccine delivery sites, including long-term care facilities, by examining patient characteristics associated with receipt of the second dose of mRNA-1273 vaccine.

METHODS: Data from patients aged ≥18 years who received their first dose of mRNA-1273 vaccine at Walgreens pharmacies and vaccine delivery sites between 12/18/2020 and 11/17/2021 were included in the analysis. Those who received other COVID-19 vaccines, aged <18 years, or opted out of Walgreens research were excluded. The primary outcome is a dichotomous variable indicating whether patients received a second dose of mRNA-1273 at Walgreens between 24 and 42 days after the first dose per CDC guidelines. Chi-squared and Student’s t-tests were conducted to determine whether there are univariate associations between patient characteristics, including individual-level and population-level factors, and second dose receipt. Multivariable logistic regression was conducted to further examine these factors.

RESULTS: A total of 4,611,163 patients were eligible for a second dose. Of those, 86% received their second dose of mRNA-1273 at Walgreens within the CDC’s recommended timeframe. The logistic regression model revealed significant predictors of receiving a second dose on time (p<0.05); patients who received their second dose on time were significantly more likely to be older, female, Asian, non-Hispanic, and drove less distance to their first dose. At the population-level, patients who received their second dose on time were significantly more likely to live in urban areas and counties that were more likely to be Hispanic, higher income, with higher unemployment.

CONCLUSIONS: Almost 90% of this study population received their second dose of mRNA-1273 vaccine per CDC recommendations. Further research should examine differences between early and late adopters and those who received a third vaccine dose, including boosters.