City officials are warning of a possible measles exposure at Union Station after someone with the highly contagious illness passed through the West Loop hub late last month.
The Chicago Department of Public Health announced Thursday that a domestic traveler from out of state with a confirmed case of measles passed through Union Station between 10:25 p.m. on Aug. 27 and 11:30 p.m. on Aug. 28. The exact date and time of the exposure is currently unknown, officials said.
If and when more information about the exposure is known, officials said updates would be available on the CDPH website.
Officials are advising that anyone concerned about exposure should monitor themselves for measles symptoms, which can include rash, high fever, cough, runny nose and red, watery eyes. Symptoms can take anywhere between seven and 21 days to surface after exposure.
The possible exposure comes in the wake of several cases of measles across the state — and amid a national resurgence of the illness nationwide.
Last week, Illinois health officials announced an outbreak of measles in Douglas County. At least four confirmed, linked cases of measles broke out in the east central county, according to the Illinois Department of Public Health. An outbreak is defined as three or more connected cases.
Meanwhile, in Kane County, two cases of measles have been announced in recent weeks. On Wednesday, the local health department reported that an individual who was vaccinated against measles had contracted the illness. The other case in the county was confirmed late last month in an unvaccinated student at an area high school, prompting the campus to shift to online learning for a day to minimize exposure.
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Measles can spread through the air when a person coughs or sneezes. It can also spread through contact with nose and throat secretions from an infected individual.
So far this year, there have been 11 cases of measles in Illinois, according to the state health department. Last year, the state had 14 cases of measles.
Measles had been declared eliminated in the U.S. in 2000, but in recent years it’s been making a comeback amid hesitation over vaccines and changing federal guidance about a number of nonmeasles vaccines. The federal government has continued to recommend measles vaccines for all children.
As of Sept. 4, there have been 3,134 confirmed measles cases in the U.S. in 2026, according to the Centers for Disease Control and Prevention. It’s the largest number of cases in decades, according to a U.S. Measles Tracker hosted by the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health.
One dose of the measles/mumps/rubella (MMR) vaccine is 93% effective, and two doses are 97% effective in preventing measles, according to the state health department.
Last month, the Illinois Department of Public Health reaffirmed its support for the American Academy of Pediatrics’ immunization schedule, which recommends two doses of the MMR vaccine for all children.
baiduhai’s Lisa Schencker and Molly Morrow of the Aurora Beacon-News contributed.