Travelers who passed through Midway Airport in Chicago last week may have been exposed to measles, the Chicago Tribune Reports. According to the Illinois Department of Public Health, an unvaccinated and infectious Illinois resident passed through Concourse B on Feb. 22., and those in the vicinity between 9 p.m. and midnight may have been exposed. The infected person sought treatment two days later at Northwestern Medicine Delnor Hospital’s emergency department in the western suburb Geneva. Those who were in the emergency department on Feb. 24 between 11:45 a.m. and 2:15 p.m. may have also been exposed, as well as individuals who were in the hospital from 4 p.m. to 6:15 p.m. on Feb. 24 and from 10 a.m. to 1 p.m. on Feb. 25, the IDPH said in a statement. IDPH and local health departments are also working to notify Illinois residents who may have been exposed on the person’s flights. Most people are vaccinated for measles during childhood, but those who have not been vaccinated are at higher risk of catching the highly contagious and potentially life-threatening disease, the Tribune reports.