Despite encouragement by 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 stand-alone Prescription Drug Plans (PDPs) for CY 2017, with little change since 2015. Read more in this study released by Manatt Health entitled Trends in Medicare Part D Benefit Design and Cost Sharing for Adult Vaccines, 2015–2017.