Flu activity in Illinois is considered widespread, meaning it's appeared in more than half of the state.
The Illinois Department of Public Health said there have been more than 120 intensive care hospitalizations and six flu-related deaths this season.
Spokesperson Melaney Arnold said the numbers are lower than at this time last year, but more cases are showing up each day.
“We do anticipate the number of ICU admissions and deaths is going to increase,” said Arnold.
“So we strongly encourage people, if they not received their flu shot yet, to go ahead and get one. It is not too late.”
Arnold said this particular flu strain is having less of an effect on older people than younger adults and children, specifically those with chronic medical conditions and pregnant women.
The flu season can last into April.