California's Health4All Kids Expansion And Health Insurance Coverage Among Low-Income Noncitizen Children.

More than one-third of US children receive coverage through Medicaid and the Children's Health Insurance Program (CHIP), but undocumented immigrant children are not eligible for public coverage in most states. California's May 2016 Health4All Kids coverage expansion allowed children with qualifying household incomes to enroll in Medi-Cal, California's Medicaid and CHIP program, regardless of their immigration status. We examined the effects of California's expansion on noncitizen children's uninsurance rates and sources of coverage, using data from the 2012-18 American Community Survey. California's expansion was associated with significant increases of about 9 and 12 percentage points in any coverage and public coverage, respectively. The estimated increase in any coverage translates to a 34 percent decline in the uninsurance rate relative to the preexpansion rate among noncitizen children (26 percent). Counties with an existing program to reduce children's uninsurance rates experienced an increase in coverage earlier than those without a program in effect before the statewide expansion.