Administrative Burden and Vaccination Uptake Disparities: Evidence from Medicaid Participation Among Low-Income Adults.

CONTEXT: During the early COVID-19 vaccine rollout, large disparities in uptake emerged across income and insurance groups, despite the vaccine being made available at no cost to recipients. Medicaid, as the largest public insurance program for low-income adults, was positioned to play a key role in supporting equitable COVID-19 vaccination uptake. However, administrative burden (AB) and fragmented enrolment processes may have inhibited participation.

OBJECTIVE

To estimate the relationship between Medicaid coverage and COVID-19 vaccine uptake among low-income adults, and assess whether differences in access or engagement underlie observed disparities.

DESIGN

Cross-sectional analysis of individual-level survey data using entropy balancing and robustness checks including instrumental variables.

SETTING AND

PARTICIPANTS

Adults aged 18-64 with household income below 200% of the federal poverty level, drawn from the US Census Household Pulse Survey (January-September 2021).

MAIN OUTCOME MEASURES: Self-reported receipt of at least 1 COVID-19 vaccine dose or reported intention to vaccinate.

RESULTS

After balancing observed covariates across insurance groups, Medicaid coverage was associated with a 3.4 percentage point increase in vaccine uptake compared with being uninsured, but a 6.9 percentage point gap remained relative to private insurance. Additional analyses suggest unobserved barriers may further depress vaccine uptake among those insured through Medicaid. These disparities seem driven in part by administrative burden (AB): Medicaid recipients facing more complex enrolment systems were less likely to use available vaccination services, underscoring how program design can shape downstream health behaviors even postenrolment.

CONCLUSIONS

AB and access fragmentation likely contributed to lower COVID-19 vaccination rates among Medicaid enrollees, even when vaccines were free and insurance was nominally available. Addressing these policy-mediated barriers may improve equity in vaccination uptake among low-income adults in future public health interventions.