Chicago health officials, together with Kane County and Wisconsin health departments, released a public warning on September 14, 2026, about a growing measles outbreak in southwestern Wisconsin and a possible exposure at Chicago’s Union Station. The alert follows more than 160 confirmed measles cases in Wisconsin and two cases reported in Kane County this year.
Health officials in Wisconsin say the disease has spread rapidly through the southwestern part of the state, where the majority of the 160 cases have been identified. Measles is known for its high transmissibility, and the concentration of cases has prompted neighboring states to monitor travel‑related risk.
In Kane County, two measles cases have been confirmed in 2026. One of those cases is linked to a vaccinated individual, highlighting that infection can still occur despite immunization, though the vaccine remains the primary protection. No additional cases have been reported in Chicago proper.
The warning emphasizes that travelers moving between northern Illinois and southwestern Wisconsin, especially those using Chicago Union Station, could be exposed to the virus. Officials advise people to verify their vaccination status, seek medical attention if fever or rash develops, and consider postponing non‑essential travel to the affected region until the outbreak is contained.
Chicago and Kane County health departments will continue to share information with Wisconsin officials and will update the public as new data become available. The coordinated response aims to limit further spread of measles across state lines and protect residents of both states.