Childhood Insurance Dynamics Predict Medicaid Cuts Will Widen Gaps

After President Donald Trump signed the Big Beautiful Bill into law in July—which is projected to slash $900 billion in federal Medicaid spending over the next 10 years—a new JAMA report shows that these cuts could critically impact US children.^1-3

According to the new research based on national data, between 2015 and 2019, 61% of children in the US were at some point enrolled in Medicaid or the Children’s Health Insurance Program (CHIP), and 42% experienced a period without health insurance before they reached 18 years old.³

Additionally, among those who were born into a family with Medicaid or CHIP, the rate of children who also experienced a period of no insurance was higher in states that did not expand Medicaid under the Affordable Care Act (ACA) compared with states that did (59% vs 36%).

The authors emphasized that their estimates showcase the critical role that Medicaid and CHIP play in childhood, despite persisting insurance gaps. They also warned that proposed cuts from the Trump Administration will only exacerbate these issues.

“Although all states are required by federal law to provide 12-month continuous eligibility for children in Medicaid or CHIP since 2024, CMS recently announced it will not approve future efforts to address coverage gaps through multiyear continuous Medicaid or CHIP eligibility for children (eg, continuous coverage from birth until age 6 years). Combined with pending Medicaid cuts targeting the adult expansion population, childhood insurance gaps may worsen relative to already substantial post-ACA, prepandemic baseline estimates,” the authors explained.

The US health care system is fragmented, with wide state variation in publicly funded insurance programs such as Medicaid, CHIP, and ACA Marketplaces. These programs cover nearly half of all children annually, but eligibility and participation vary across states. Disruptions in coverage—whether full-year uninsurance, gaps, or transitions between programs—are linked to delayed care and unmet medical needs. Prior studies often relied on short-term follow-up, which may underestimate the true extent of these disruptions.

Recent shifts in Medicaid and CHIP policy, including continuous coverage requirements during the COVID-19 public health emergency and subsequent federal decisions to limit multiyear continuous eligibility, highlight the importance of understanding children’s long-term insurance dynamics. This study estimated the proportions of children who were ever enrolled in Medicaid or CHIP and those who were ever uninsured, providing a critical baseline for evaluating how new policy changes may affect children’s coverage stability.

The study examined insurance coverage for US children from birth through age 18 under post-ACA, prepandemic conditions using data from 2015 to 2019. Data sources included national surveys (Survey of Income and Program Participation [SIPP], Medical Expenditure Panel Survey [MEPS]), CDC natality records, state Medicaid and CHIP policy information, and US life tables. A simulated cohort of 100,000 children was created to reflect national birth patterns by state, race and ethnicity, and insurance status at birth.

A microsimulation model projected monthly insurance status in 5 categories (Medicaid/CHIP, Marketplace, employment-based, other, or uninsured) through 18 years of life. Insurance transitions were estimated using k-nearest neighbor matching on demographic, income, and policy variables, with state of residence and family income updated annually. Outcomes included time spent in each insurance type, number of transitions, and proportions ever uninsured or ever enrolled in Medicaid/CHIP. Sensitivity analyses and bootstrapping were used to assess uncertainty, with internal and external validation conducted against SIPP and MEPS estimates.

The model projected that US children experienced an average of 2.5 insurance switches from birth to age 18. By their 18th birthday, 79% had ever been enrolled in employment-based insurance, 61% in Medicaid or CHIP, and 42% had been uninsured at some point. Just under 58% of children maintained continuous coverage through childhood, although only 26% remained consistently covered by employment-based or other private insurance and 14% remained consistently covered by public programs.

Children who were ever enrolled in Medicaid or CHIP spent a median of nearly 11 years in the program, with Hispanic and non-Hispanic Black children showing the highest participation and longest enrollment durations. State policies strongly influenced outcomes: among children born with Medicaid or CHIP, 59% in nonexpansion states were ever uninsured compared with 36% in expansion states, with longer periods of uninsurance observed in the most restrictive policy environments.

The study found that publicly and privately insured children are often overlapping populations: approximately 40% of US children were covered by both Medicaid or CHIP and employment-based insurance at different points during childhood. This overlap suggests that changes to public insurance policies could influence many children who also have access to private coverage, and vice versa.

The analysis also highlighted the central role of Medicaid and CHIP in coverage for Hispanic and non-Hispanic Black children, who were more likely to enroll and spent longer cumulative time in these programs. The findings align with prior data showing that Hispanic and non-Hispanic Black individuals comprised a larger share of Medicaid beneficiaries in 2019 than in the general population. As such, Medicaid and CHIP policies have substantial potential to reduce health disparities by ensuring coverage for historically underserved populations.

The authors concluded, “Future studies can create and follow up single-year age cohorts using longitudinal claims to produce comparable estimates to further validate these findings.”

References

1. President Trump’s One Big Beautiful Bill is now the law. The White House. July 4, 2025. Accessed September 24, 2025. https://www.whitehouse.gov/articles/2025/07/president-trumps-one-big-beautiful-bill-is-now-the-law/

2. Shaw M. Proposed GOP Medicaid cuts threaten loss of coverage for millions. AJMC^®. May 12, 2025. Accessed September 24, 2025. https://www.ajmc.com/view/proposed-gop-medicaid-cuts-threaten-loss-of-coverage-for-millions

3. Shen Y, Sommers BD, Hatfield LA, Hayes C, Pandya A, Menzies NA. Insurance dynamics during childhood in the fragmented US health system.  JAMA. Published online September 24, 2025. doi:10.1001/jama.2025.15488