A person who visited a Chicago airport and hospital last week had the measles, the Illinois Department of Public Health says—meaning those who were in the same locations at the same time could possibly be infected. The Chicago Tribune reports that the unidentified Illinois resident came in to Midway International Airport's Concourse B on Friday, Feb. 22, and that passengers who were in the airport between 9pm and midnight on that date may have been exposed. The unvaccinated patient then visited the ER at Northwestern Medicine Delnor Hospital in Geneva a couple of days later; health officials say anyone in that facility's ER on Feb. 24 between 11:45am and 2:15pm, or in the hospital overall that day from 4pm to 6:15pm, as well as the next day from 10am to 1pm, should be on alert.
"These are the only known public locations in Illinois where exposures occurred," health officials said in a statement, per CNN. USA Today notes that individuals who were possibly infected may not even see symptoms—which include fever, dry cough, a runny nose, and the telltale blotchy skin rash—until after St. Patrick's Day, as they can often take weeks to manifest. If anyone does suspect they were exposed, health officials recommend calling a health provider before heading in for testing, so as not to expose others. The health department notes that those who regularly got their measles shots as kids are "not at high risk," and that it's "most concerned" about the unvaccinated, per NBC News. (A visiting 5-year-old boy returned measles to a country.)