The new policy was sparked by an apparent increase in flu cases at the South Side hospital. Any patients and visitors with the symptoms going to the hospital's clinic must wear a mask.
Children under age 12 and those with a fever, cough, sore throat, runny nose or nasal congestion will not be allowed to visit patients.
"Something that may present as a cold or a minor infection in an otherwise healthy person could have really severe consequences to our patients in the hospital," said
Dr. Allison Bartlett, a University of Chicago pediatric infectious disease specialist.
The temporary change aims to stop the spread of the illness. Officials say based on the flu season in Australia, which hits earlier, Chicago may get hit hard.
According to Cook County Department of Public Health data, influenza activity is increasing.
During the week ending Dec. 16, 385 people have tested positive for influenza and 31 ICU hospitalizations were reported since September.
That's compared to last year when 55 people tested positive for influenza and only 13 ICU hospitalizations were reported during the same time.
The flu bug increase is affecting a wide range of age groups -- not just kids and the elderly.
Health officials say because the flu season got a late start, the number of people getting sick could be on the rise.
Reason why they're encouraging anyone who hasn't gotten a flu shot to get one.
"It's not perfect, but 50 percent protection is better than no protection," Bartlett said.
The Chicago Department of Public Health sponsored flu vaccine clinics this month. Experts suggest the 3 Cs when combating the spread of the flu: COVER your face when you sneeze/cough; CLEAN your hands and CONTAIN by staying home.