The Impact of the Medicaid Reimbursement Bump on Influenza Vaccination Rates Among US Teens: Evidence from the National Immunization Survey-Teen 2011-2020.

Background: Many adolescents do not receive basic preventive care such as influenza vaccinations. The Affordable Care Act (ACA) temporarily increased Medicaid reimbursements for primary care services, including vaccine administration, in 2013 to 2014. The objective of this study is to assess the impact of reimbursement increases on influenza vaccination rates among adolescents with Medicaid.

Methods: This repeated cross-sectional study used a difference-in-difference approach to compare changes in annual influenza vaccination rates for 20,884 adolescents 13 to 17 years old covered by Medicaid with adequate provider-reported data in 18 states with larger extended (>$5, 2013 to 2019) versus larger temporary (2013 to 2014 only) versus smaller reimbursement changes. We used linear probability models with individual-level random effects, adjusting for state and individual characteristics and annual time trends to assess the impact of a Medicaid vaccine administration reimbursement increase on annual influenza vaccination.

Results: Mean Medicaid reimbursements for vaccine administration doubled from 2011 to 2013 to 2014 (eg, from $11 to $22 for CPT 90460). States with smaller reimbursement changes had higher mean reimbursements and higher adjusted vaccination rates at baseline (2011) compared with states with larger temporary and extended reimbursement changes. The reimbursement change was not associated with increases in influenza vaccination rates.

Discussion: Influenza vaccination rates were low among adolescents with Medicaid throughout the study period, particularly in states with lower Medicaid reimbursement levels before the ACA.

Conclusion: That reimbursement increases were not associated with higher vaccination rates suggests additional efforts are needed to improve influenza vaccination rates in this population.