The state’s first confirmed measles case of the year was detected in southern Illinois, the Illinois Department of Public Health reported Wednesday.
The department said an adult tested positive for measles at a clinic in “far southern Illinois,” but did not share a more specific location. It is the only case in Illinois the state is aware of and the risk of community transmission for the general public remains low. The department did not say if the person is vaccinated.
The clinic where the person sought care is working on identifying if anyone was exposed or also infected. Measles is a highly contagious disease — one person can infect up to 18 individuals. In contrast, the flu’s infection rate is about one to two people.
On Thursday, the health department identified seven locations, all in Marion, where people may have potentially been exposed to measles from April 7-15:
- Don Sol Restaurant
- Legacy Fitness
- Walmart
- Kroger
- Wonder Wash Laundry
- Easy Coin Laundry
- Small Star Laundry
“This first reported case of measles in Illinois in 2025 is a reminder to our Illinois residents that this disease can be prevented with up-to-date vaccination,” the agency’s director, Dr. Sameer Vohra, said in a statement. “With hundreds of cases being reported nationally, we have been working closely with our local public health and health care partners to prepare for any potential measles cases in Illinois.”
Anyone who hasn’t been vaccinated against measles — including infants — are of most concern, officials said.
“Anyone exposed and not immune to measles should stay alert for any signs and symptoms of measles such as rash, high fever, cough, runny nose, and red, watery eyes, and notify their local health department if they become symptomatic,” the department said in a news release.
The last time Illinois had a measles outbreak was early 2024 in Chicago. At least 67 cases were confirmed during that outbreak, which was mainly tied to the city’s migrant shelters.
But ongoing measles outbreaks elsewhere in the country have state health officials on alert. More than 680 cases and three deaths have been tied to an outbreak in Texas and New Mexico. The federal Centers for Disease Control and Prevention reports at least 800 cases total nationwide, including in Indiana. The vast majority of infected individuals are unvaccinated, according to the CDC.
Medical professionals and health officials stress that the best way to protect against measles is the two-dose MMR vaccine, which covers measles, mumps and rubella. The first dose is given when a child is between 12 and 15 months old. The second dose is given between the ages of 4 and 7. That first dose alone gives 93% immunity and two doses supplies 97%. Anyone at any age can get vaccinated.
Symptoms can take from one to three weeks to appear after exposure to someone with measles, according to health officials.
The health department recently unveiled a new data dashboard to help assess the potential severity of any school outbreaks of measles, if one were to happen in Illinois.
For more information about measles, contact your health care provider, or visit the Illinois Department of Public Health webpage on measles or the CDC’s measles site.