April 15 update: In a statement, the franchise operator identified the restaurant as a McDonald's in the Loop.

"We recently learned that an employee at our restaurant located at 180 W. Adams in Chicago tested positive for the coronavirus and is currently under medical care. This employee has not been in the restaurant since March 17, more than 20 days ago," Rod Lubeznik, the McDonald's franchise operator, said in the statement. "As soon as we were notified, we alerted our employees. We have not been informed of any other employee at this location testing positive."

He said best practices are being followed, including disinfecting the restaurant every night, providing workers with masks and gloves, and having wellness and temperature checks at the beginning of each shift.

Earlier:

Workers at a downtown Chicago McDonald's have filed a federal complaint saying managers at a franchisee-owned restaurant did not alert all employees that a night-shift worker contracted COVID-19 and saying the restaurant is not doing enough to protect employees.