Illinois measles cases hit 23 in 2026, most from Douglas, Moultrie counties outbreak

Illinois has confirmed 23 measles cases so far this year, most of them tied to an outbreak among unvaccinated people in central Illinois, and state health officials are urging residents to make sure they're vaccinated.

Sixteen of the cases are part of an outbreak in Douglas and Moultrie counties that began in August, the Illinois Department of Public Health said. The people infected were unvaccinated or had an unknown vaccination history. Unrelated cases have also been identified recently in Kane and Madison counties.

The department says the risk to residents remains very low.

"While Illinois is fortunate to have high vaccination rates overall, there are still areas across the state with lower vaccination rates where people are at high risk," said Dr. Sameer Vohra, the department's director.

Local health departments have given more than 200 doses of the measles, mumps and rubella vaccine since the outbreak began, including through weekly vaccination events and walk-in hours. Recent exposure sites include Chicago's Union Station and the Salt + Smoke restaurant in Edwardsville. The Chicago Department of Public Health has confirmed two measles cases in people who traveled through Union Station on Sept. 10, 12 and 13, as previously reported.

Two doses of the MMR vaccine are 97% effective at preventing measles, and a single dose is 93% effective. Unvaccinated people 6 months and older who are exposed should call a clinician or local health department right away, since quick treatment can prevent the disease or make it less severe.

Measles was declared eliminated in the U.S. in 2000 but has come back in recent years as vaccination rates have dropped. As of early September, the U.S. had recorded more cases this year than in any year in more than three decades, according to CBS News' tracking of CDC data.