The University of Southern California study, published in JAMA Network Open on October 5, 2026, found that emergency room visits by foreign-born patients at three Los Angeles County hospitals fell by over 20% in the first four weeks after immigration enforcement expanded in June 2025. The analysis covered Los Angeles General Medical Center, Harbor-UCLA Medical Center, and Olive View-UCLA Medical Center. By October 2025, the gap between foreign-born and U.S.-born patient visits had shrunk to 10%, but the data also showed that foreign-born patients admitted to the hospital did so at higher rates. Mexican-born patients experienced a 4.8 percentage-point rise in admissions, Central and South American-born patients saw a 5.1-point increase, and Asian-born patients had a 2.5-point rise.
Researchers stressed that the study only identifies an association, not proof, that enforcement activity caused the decline. It also does not clarify where patients who avoided emergency care sought treatment instead. The data tracked country of birth rather than immigration status, meaning some foreign-born patients could be naturalized citizens or lawful residents. Despite these limitations, the findings suggest that heightened enforcement may discourage immigrant patients from seeking acute care when needed, with potential health risks for patients and financial burdens for health systems.
Delayed Care Risks for Immigrant Families
Sarah Axeen, PhD, the study’s lead author and assistant professor at USC’s Keck School of Medicine, warned that delayed emergency care can have severe consequences. Conditions like chest pain, stroke symptoms, or heavy bleeding become harder to treat when ignored. For households with foreign-born parents, grandparents, or caregivers—including mixed-status families where children are U.S. citizens—one adult’s hesitation could determine whether a sick child or elderly relative reaches the ER in time.
Federal law under the Emergency Medical Treatment and Labor Act (EMTALA) prohibits hospitals accepting Medicare from denying care based on immigration status. Los Angeles County’s Department of Health Services reaffirmed this stance in January 2025, stating its commitment to providing high-quality, equitable, and compassionate care to all, regardless of immigration status. The department also emphasized it does not collaborate with immigration enforcement and maintains strict patient confidentiality protocols. The higher admission rates among foreign-born patients who did visit the ER suggest some may have delayed care until conditions worsened, while others with milder issues stayed home.
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Enforcement Surge Triggers Visit Drop
The sharpest drop in visits occurred in early June 2025, coinciding with enforcement operations in downtown Los Angeles and nearby communities. The USC Schaeffer Center’s analysis compared the 12 months before enforcement expanded with the four months after, focusing on the three county-run safety-net hospitals as key providers for immigrant communities.
Chicago Shows Parallel Pediatric Misses
Separate data from Chicago revealed a similar trend: missed pediatric appointments rose among Spanish-speaking families after the federal Operation Midway Blitz. The Chicago study focused on scheduled children’s visits.
The study’s limitations include its focus on three hospitals in one county and its reliance on country of birth rather than immigration status. It also does not show whether visit levels have since recovered or whether delays led to measurable harm. Open questions remain about whether similar patterns appear in other cities.
The research team combined electronic health records from the three county hospitals with self-reported country of birth information. The study excluded any variables that might identify individual immigration status, focusing instead on broad patterns of emergency department utilization. Methodologically, investigators compared patient volumes before and after enforcement expanded, capturing only a snapshot of visits. Because the comparison relied on a single geographic area, findings cannot be generalized to all regions. The authors emphasized that observed timing associations do not establish direct causality.
