A vaccinated DuPage County resident has tested positive for measles after returning from international travel, and anyone who was in Terminal 5 at O'Hare International Airport on Thursday, Oct. 15, between 4:20 p.m. and 7 p.m. may have been exposed. The DuPage County Health Department announced the case on Wednesday, Oct. 21, calling it a rare breakthrough infection, according to the county health department's news release.
It is the county's first measles case of 2026. Officials did not release the person's age, hometown, number of vaccine doses, or travel destination.