Missouri saw some of the most notable shifts in health coverage in the nation between 2023 and 2025, prior to the open enrollment period now underway. During this period, Affordable Care Act (ACA) marketplace enrollment grew 62% — far above the 49% increase nationally — while Medicaid enrollment declined across every county.
A new policy brief and dashboards from the Center for Advancing Health Services, Policy & Economics Research (CAHSPER) at Washington University in St. Louis show how these trends unfolded across the state of Missouri, and explore how policy changes during and after the pandemic contributed to these trends.
How did we get here?
Missouri’s coverage landscape has been shaped by rapid, overlapping policy changes over the past several years.
2020-2023 — Continuous Medicaid coverage during the COVID-19 pandemic
During the pandemic, states were not allowed to remove anyone from Medicaid for any reason unless the person moved out of the state or voluntarily ended coverage. These rules paused all routine disenrollments during the COVID-19 crisis and kept millions insured at a time of major economic and public health instability.
2021 — Congress enacts enhanced premium tax credits
The American Rescue Plan expanded premium tax credits, drastically reducing monthly out-of-pocket marketplace premiums for many low- and middle-income families. These enhanced credits made private ACA marketplace coverage far more affordable and contributed to record marketplace growth nationwide. These credits are scheduled to expire at the end of 2025 unless Congress acts.
2023 — Medicaid redeterminations resume
When the continuous coverage protections ended, Missouri — like states nationwide — began reviewing eligibility again. This is commonly referred to as the “unwinding” from the public health emergency. Many people lost Medicaid even if they remained eligible, often because of paperwork issues, outdated contact information or administrative hurdles. Missouri experienced one of the largest Medicaid enrollment declines in the country during this period.
2023-2025 — Marketplace enrollment surges as Medicaid declines
As people lost Medicaid, some shifted into subsidized ACA marketplace plans — particularly as enhanced premium tax credits lowered costs. Marketplace enrollment in Missouri rose from 257,629 in 2023 to 417,000 in 2025, a 62% increase, according to the CAHSPER policy brief.
What the analysis shows
- Counties with larger Medicaid losses tended to see stronger marketplace gains, indicating many residents may have shifted to marketplace plans after losing Medicaid.
- Marketplace growth matched or exceeded Medicaid declines in 82.6% of Missouri counties, showing how the marketplace functioned as a safety valve during the unwinding.
- Marketplace enrollment increases were especially pronounced in higher-poverty counties, where enhanced federal tax credits made private coverage newly affordable.
Policy implications
The brief recommends several steps to support coverage stability in Missouri:
- Reduce barriers in the Medicaid renewal process, including paperwork challenges and confusing notices.
- Strengthen enrollment assistance, especially in counties where Medicaid losses did not result in marketplace transitions. Expand in-person assistance, helplines and multilingual support.
- Target outreach to communities most affected by disenrollment, working with trusted local organizations.
- Continue tracking enrollment trends, especially as enhanced premium tax credits approach their December 2025 expiration.
About the analysis
The authors of the policy brief are Claire Ami Pavlides, a master’s in public health candidate, statistical data analyst Sarah A. Eisenstein and Timothy D. McBride, center co-director and the Bernard Becker Professor in the WashU School of Public Health.
The analysis draws on data from the Missouri Department of Social Services, the Centers for Medicare & Medicaid Services, the U.S. Census Bureau and the U.S. Department of Agriculture.
This work is supported by the Missouri Foundation for Health.
The full brief and interactive dashboards are available on the CAHSPER website.
