Vaccination utilization among U.S. adults is low, and well below the Healthy People 2020 Targets, despite widespread availability of safe and effective vaccines and long-standing use recommendations by the Centers for Disease Control and Prevention (CDC) and the Advisory Committee on Immunization Practices (ACIP). The 2010 Affordable Care Act (ACA) eliminated some coverage and financial access barriers to adult vaccinations covered by private health insurance and Medicaid, but it did not substantially change vaccine utilization or cost sharing for beneficiaries enrolled in Medicare Part D. The law requires that Medicare Part D plans cover all commercially available vaccines not already covered under Medicare Part B, if the vaccine is reasonable and necessary to prevent illness. Cost sharing guidelines for vaccines in Part D remained unchanged under the ACA. This study shows that despite encouragement by the Centers for Medicare & Medicaid Services (CMS) for Part D plans to provide vaccines without cost sharing to incentivize the use of these preventive services, about 4% or less of Medicare Part D enrollees had access to the vaccines examined in this study with no cost sharing, depending on the vaccine, in either Medicare Advantage Part D Prescription Drug Plans (MA-PDPs) or standalone Prescription Drug Plans (PDPs) for CY 2017, with little change since 2015. Importantly, no PDPs offered zero-dollar cost sharing for the vaccines under study between 2015 and 2017.

Medicare Part D plans include MA-PDPs and PDPs; PDPs may be purchased by beneficiaries enrolled in traditional Medicare Part A and B programs. In January 2017, Part D enrollment across all types of Part D plans was approximately 42.2 million, with about 59% in PDPs. Enrollment increased from 38.6 million in January 2015 (61% in PDPs). This study focuses on non-low income subsidy (non-LIS) Part D enrollees in MA-PDPs and PDPs who can face high cost sharing, unlike enrollees eligible for LIS who, by statute, have reduced cost sharing. This study also excludes enrollees from demonstrations, national programs for all-inclusive care for the elderly (PACE) plans, employer group waiver plans (EGWPs), employer-direct contract plans, and plans where Medicare has suppressed public use data for various reasons.