A majority of US children rely on Medicaid or CHIP, new study finds

Sep. 24—A majority of children in the United States rely on Medicaid or the Children's Health Insurance Program at some point by their 18th birthday, and many experience periods of coverage loss, according to a study published Wednesday in the journal JAMA.

By their 18th birthday, about 3 in 4 children nationwide relied on Medicaid, CHIP (which subsidizes health care for children and pregnant women in families that earn too much for Medicaid), or the subsidized insurance marketplaces established through the 2010 Affordable Care Act — or experienced a period during their childhood without health insurance, the study found.

Researchers from the Harvard T.H. Chan School of Public Health conducted estimates based on analyses of national data from 2015 to 2019, looking at cumulative coverage rates over the course of childhood.

The study comes as states grapple with federal Medicaid cuts under President Donald Trump's One Big Beautiful Bill Act. The tax and spending law will reduce Medicaid funding by $1 trillion and cut enrollment by 10 million to 15 million people over the next decade, according to projections by the Congressional Budget Office.

About 42% of children suffered a period of losing health coverage at any point in time by their 18th birthday, the Harvard researchers found, and 61% had at some point enrolled in Medicaid or CHIP. About 78.5% were at some point enrolled in employment-based insurance.

Rates of children who lost insurance coverage were higher in states that hadn't expanded Medicaid income eligibility under the Affordable Care Act, often known as Obamacare. Roughly 59% of children in non-expansion states had periods without any insurance coverage — compared with 36% in expansion states. Overall, about 2 in 5 children experienced periods without health insurance, the study found.

And states with the strictest income thresholds saw the highest share of kids losing coverage who previously were covered by Medicaid or CHIP at birth.

"Upcoming changes to Medicaid could affect a significant portion of children and worsen already substantial insurance gaps," senior author Nicolas Menzies,an associate professor of global health and faculty member in the school's Center for Health Decision Science, said in a statement.

"We're particularly worried about explicit loss of public insurance eligibility for noncitizen children; spillover effects through parental Medicaid coverage losses due to work requirements and more eligibility checks; and state-level cuts to Medicaid."

Stateline reporter Nada Hassanein can be reached at [email protected].

YOU MAKE OUR WORK POSSIBLE.

© 2025 Stateline.org. Visit www.stateline.org. Distributed by Tribune Content Agency, LLC.