The visitor restrictions at the company's Evanston, Skokie, Glenbrook and Highland Park hospitals came just two days after University of Chicago hospital instituted their restrictions for the same reason.
Visitors showing symptoms including fever, cough, or sore throat will not be allowed to see patients. Additionally, no visitors under the age of 18 will be permitted in patient care units. Visitors will also be limited to two at a time for each patient.
The temporary change is meant to protect patients.
Anyone who hasn't gotten a flu shot yet is urged to get one.