Blog Center for Advancing Health Services, Policy & Economics Research

Two years after Medicaid expansion began, enrollment peaks; effects of unwinding loom

Written by Timothy McBride, PhD, MS, Bernard Becker Professor at the Brown School and co-director of the Center for Advancing Health Services Policy and Economics Research


On July 1, Missouri reached a milestone, completing two years since the official start of Missouri Medicaid expansion. Although voters approved expansion to begin on July 1, 2021, due to litigation resolved by the Missouri Supreme Court, enrollment began on October 1, 2021. According to data from Missouri’s Department of Social Services posted on its weekly caseload counter, enrollment in the Medicaid Adult Expansion Group (AEG) has been robust, peaking at 344,108 on June 16, and leveling out to 342,085 by the end of June 2023 (Figure 1).

It is notable that when the expansion started, Governor Mike Parson’s administration projected that about 274,000 Missourians would enroll in the expansion in the first year.  By December of 2022, that level of over 274,000 enrollees was hit and as noted, enrollment growth continued until peaking at about 344,000.

In the first two weeks of July, enrollment dropped (a net drop of over 5,000). This may represent the first measured effect of what has been called the “unwinding”. The unwinding is a recertification of Medicaid enrollees, including those who were enrolled during the pandemic, and by law, the state could not disenroll recipients until July 1. Until the state officially reports the unwinding data later in July, the full effect of the unwinding on Medicaid expansion enrollment will not be known. Nationwide through July 20, over 3 million Medicaid enrollees lost coverage due to the unwinding.  

Enrollment in the Medicaid expansion has been relatively stagnant since the beginning of March when enrollment in the AEG hit 321,595. The following 19 weeks has been below the moving average change, with the exception of four of those weeks (see Figure 2). It is not clear why enrollment growth stagnated after March, and further research into this will be needed to determine why this has happened.

Fig. 2

It is expected that the effects of unwinding will hit other categories of Medicaid recipients harder (e.g., children, custodial parents, pregnant women, disabled, and older adults) since the Medicaid expansion enrollees first signed up in mid-2021, and perhaps very recently, and thus they may likely still be eligible for the program.  Also, it is notable that the enrollment numbers shown here are net enrollment changes, which means they account for people added to the rolls (new enrollees) minus those who disenrolled. Some people losing coverage in other categories (e.g., custodial parents) due to ineligibility may still be eligible under the Medicaid expansion’s more generous eligibility requirements.