Effects of Medicaid Expansion on HPV Vaccination Uptake Among Adolescents in the United States: Difference-in-Differences Analyses From 2011 to 2022.

Objectives. To determine if Medicaid expansion was associated with increased human papillomavirus (HPV) vaccination among adolescents in the United States. Methods. We conducted a quasi-experimental study using generalized difference-in-differences on National Immunization Survey‒Teen data from 2011 to 2022 among adolescents aged 13 to 17 years, comparing HPV vaccination in Medicaid expansion states to nonexpansion states by sex and race/ethnicity subgroups. Results. There was a significant 10.1-percentage-point increase in HPV vaccination among male adolescents in expansion states (95% confidence interval [CI] = 8.9, 12.4; P < .001). Significant increases in HPV vaccination were observed among all male racial subgroups, with largest effects among Black, Latino, and other or multiple races. No effect was observed among female adolescents or any racial subgroup. Conclusions. Medicaid expansion was associated with significant increases in HPV vaccination among male adolescents, with no effects observed among female adolescents. All male race/ethnicity subgroups showed increases, with Black, Latino, and other or multiple race/ethnicity male adolescents having the largest effect. Public Health Implications. Medicaid expansion is an appropriate and effective policy for increasing HPV vaccination uptake for priority populations, including historically marginalized racial/ethnic groups and male adolescents. (Am J Public Health. Published online ahead of print June 26, 2025:e1-e9. https://doi.org/10.2105/AJPH.2025.308165).