Health officials warned of possible measles exposure at Chicago O’Hare’s Terminal 1 on April 22–23 between 10 a.m. and 8 p.m. An infected traveler spent several hours in the terminal; because measles is highly contagious and can linger in the air for up to two hours, many passersby could have been exposed.

The individual had received one MMR dose, later developed a rash on April 25, tested positive, and is isolating. A second measles case was reported in the same Illinois county days later; officials haven’t confirmed a link.

If you were in Terminal 1 during those hours, monitor for symptoms for 21 days after exposure: fever, cough, runny nose, red eyes, and a spreading rash. If symptoms appear, call a healthcare provider before showing up so they can arrange safe evaluation and reduce potential spread.

Vaccination is the best protection: two MMR doses are \~97% effective. Check your records—especially for children, travelers, and anyone unsure of their status—and get vaccinated if needed.