IDPH reports highest single-day COVID-19 cases since mid-September Ryan Voyles 3 years ago The Illinois Department of Public Health reported 4,267 new COVID-19 cases on Thursday, the highest single-day total since mid-September.To access this content, you must purchase 1 Year Health News Illinois Subscription or 1 Year Group Subscription - Up to 5 Users, or log in if you are a member.