2 measles cases confirmed in Cook County: 1 in Chicago, 1 in suburbs
Two measles cases have been confirmed in Cook County amid the latest 2025 outbreak, public health officials announced Wednesday.
They are the first two such cases in Cook County this year.
According to a joint release from the Chicago, Cook County, and Illinois departments of public health, one of the patients is an adult from an unspecified place in suburban Cook County whose vaccination status is unknown.
The vaccination status of this person is unknown. The patient presented to an area hospital on Monday, April 28, and was quickly isolated, officials said.
"Kind of flulike feelings; like I say, a cough or runny nose, and by the time the rash has occurred, they've actually already been infectious to other people for four days," said Dr. Mark Dworkin, the associate director of epidemiology at the University of Illinois Chicago School of Public Health.
The other case involved an adult Chicago resident who traveled internationally through O'Hare International Airport in early April. This person had previously had one dose of the MMR vaccine, found a rash on Friday, and has been isolated at home since being diagnosed.
The Chicago Department of Public Health has assembled a list of places where the Chicago patient went and where people might have been exposed.
- Monday, April 21: Fittingly Delicious, 3939 W. Irving Park Rd.
- Tuesday, April 22: O'Hare International Airport, 10 a.m.-8 p.m., especially Terminal 1
- Wednesday, April 23: O'Hare International Airport, 10 a.m.-8 p.m., especially Terminal 1
- Friday, April 25: Aldi: 7235 39th St., Lyons, 10 a.m.-12:30 p.m.
- Sunday, April 27: Shell: 3901 S. Harlem Ave., Stickney, 10 a.m.-12:30 p.m.
- Monday, April 28, Mobil: 2945 S. Harlem Ave, Berwyn, 10:20 a.m.-1 p.m.
"In fact, on one of the dates that they talked about being in O'Hare Terminal 1, I was there," Dworkin said. "I was traveling to the Centers for Disease Control for a conference, all about outbreaks, including a measles outbreak that had occurred in Cook County last year."
While Dworkin was at the airport at the time of exposure, he is fully vaccinated against measles. He said those unvaccinated at any of the places the patients stopped while contagious should take heed to the health alert.
"This is not a crisis, but it's certainly the beginning, very likely, of more cases to come," said Dworkin.
Anyone who may have been exposed should notify their healthcare provider if they are unsure about their measles vaccination status. Anyone who develops symptoms should notify their health care provider or a health care facility before going to a doctor's office or an ER, so as to ensure arrangements are made so no one is exposed.
CDPH originally listed the Independence Branch of the Chicago Public Library as a measles exposure location on April 21, but on Thursday officials said they have determined the patient did not visit the library on that day. No one who was at the Independence Branch library on April 21 needs to take any additional action to protect themselves from measles.
Meanwhile, while measles vaccination is best, Dworkin added that people have options if they refuse to get the shots, or have a weakened immune system or underlying condition.
"Wearing a mask is a very good idea to reduce the chances," he said.
While measles cases are popping up across the country and have hit Cook County, Dworkin said health departments will continue to push to contain the outbreak before it worsens.
"But I'm pretty confident that we will see some more cases and be dealing with this for a little while," he said.
As of last week, there had been 884 measles cases in this current outbreak, which started in Texas.
Chicago saw its own measles outbreak just last year — affecting in particular the migrant shelter in operation at the time in Pilsen. There were 67 cases reported in the March and April 2024 Chicago area outbreak altogether.
Public health officials confirmed Chicago's first case of measles since 2019 on March 7, 2024. The next day, the city saw its first measles case at the since-closed Pilsen migrant shelter at 2241 S. Halsted St.
A total of 57 migrants at the shelter ended up testing positive for measles during March and April last year. At the time, the Pilsen shelter was the city's largest shelter for asylum seekers, with approximately 1,900 migrants living there.
Measles is so contagious that if one person has it, 90% of people close to that person who are not immune will also become infected.
Cook County Health offers free measles clinics weekly regardless of insurance.
