OBJECTIVES : Evaluate healthcare utilization during the time period influenza vaccination is most likely to occur and the ages when herpes zoster (HZ) and pneumococcal vaccination are first recommended, and identify factors associated with adult vaccination and potential missed opportunities.

METHODS : Three cohorts of adults age-eligible for vaccination were selected from the 2011-2016 MarketScan Commercial Claims and Encounters, Medicare Supplemental (CCAE/Medicare) and Medicaid databases: (1) aged 19+ years and continuously enrolled during at least one influenza season (influenza cohort), (2) continuously enrolled during a 36-month period starting the year the individual became 60 years (HZ cohort), and (3) continuously enrolled during a 36-month period starting the year the individual became 65 years (pneumococcal cohort). Influenza, HZ, and pneumococcal vaccination; potential missed opportunities (i.e., preventive care visits without an eligible vaccination); and missed encounters (i.e., lacking preventive care visits) were assessed over the continuous enrollment periods. Separate multivariable logistic regression models were used to identify patient and utilization-related factors associated with vaccination and potential missed opportunities by cohort and payer type.

RESULTS : Across all vaccines, potential missed opportunities were more prevalent in CCAE/Medicare than Medicaid, while missed encounters were more prevalent in Medicaid than CCAE/Medicare. A greater number of preventive care office-based visits, more non-preventive office-based visits, and having a family/internal medicine/pharmacist as main provider were generally associated with a greater likelihood of vaccination. In the influenza and pneumococcal cohorts, having a large proportion of visits with non-family/internal medicine providers increased the likelihood of a missed opportunity.

CONCLUSIONS : The high prevalence of missed opportunities suggests room for increasing adult vaccination rates, particularly in the office setting. Strategies for improving vaccine delivery should focus on adherence to regular preventive care, vaccine administration during preventive care visits in the office setting, assessing vaccination status/eligibility during preventive and non-preventive visits, and engagement of other healthcare providers besides family/internal medicine/pharmacist.