Possible measles exposure at O’Hare Airport has been reported by public health authorities after a confirmed case passed through Terminal 5 and later visited two suburban public locations.

Measles is caused by the measles virus and spreads through respiratory droplets and aerosol transmission. The virus can remain in the air and on surfaces for extended periods, raising concern for people who shared enclosed spaces such as airport gates and waiting areas. Officials state that people without documented measles, mumps and rubella vaccination or proof of prior infection face the highest risk of infection.

Health departments are conducting contact tracing and exposure assessment to identify individuals who may have been within the infectious radius of the case. They advise potentially exposed people to monitor for fever, cough, conjunctivitis and rash, and to call a medical provider before visiting a clinic or emergency department. Clinicians are being asked to review immunization records, consider measles in patients with compatible symptoms and follow airborne isolation and post‑exposure prophylaxis protocols.