title: The Cost of Cost-Sharing: The Impact of Medicaid Benefit Design on Influenza Vaccination Uptake.
abstract: Prior research indicates that cost-sharing and lack of insurance coverage reduce preventive services use among low-income persons. State Medicaid policy may affect the uptake of recommended adult vaccinations. We examined the impact of three aspects of Medicaid benefit design (coverage for vaccines, prohibiting cost-sharing, and copayment amounts) on vaccine uptake in the fee-for-service Medicaid population 19-64 years old. We combined previously published reports to obtain state Medicaid policy information from 2003 and 2012. Data on influenza vaccination uptake were taken from the Behavioral Risk Factor Surveillance System. We used a differences-in-differences framework, controlling for national trends and state differences, to estimate the effect of each benefit design factor on vaccination uptake in different Medicaid-eligible populations. Each additional dollar of copayment for vaccination decreased influenza vaccination coverage 1-6 percentage points. The effects of covering vaccines or prohibiting cost-sharing were mixed. Imposing copayments for vaccination is associated with lower vaccination coverage. These findings have implications for the implementation of Medicaid expansion in states that currently impose copayments.
authors.affiliation: Department of Global Health Systems and Development, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA 70118, USA. cfstoecker@tulane.edu.
authors.forename: Charles
authors.initials: C
authors.lastname: Stoecker
authors.affiliation: Department of Health Policy, The George Washington University School of Public Health and Health Services, Washington, DC 20052, USA. stewarta@gwu.edu.
authors.forename: Alexandra M
authors.initials: AM
authors.lastname: Stewart
authors.affiliation: National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. cvx9@cdc.gov.
authors.forename: Megan C
authors.initials: MC
authors.lastname: Lindley
keywords: Medicaid; influenza; vaccination