(WTTW News)

Illinois health officials on Wednesday announced the highest single-day count of new COVID-19 cases since the start of the pandemic.

There were 16,581 new and probable COVID-19 cases recorded within the past 24 hours by the Illinois Department of Public Health. 

Illinois has now seen more than 2 million COVID-19 cases and at least 27,357 deaths since the pandemic began in early 2020. The state’s seven-day statewide test positivity rate is now 7.9%, according to IDPH data, which also shows that 66 people died of COVID-19 in the past 24 hours.

This is at least the second time this week Illinois has set a record-high number of new cases in a single day for 2021. Monday’s 12,330 new cases had been the most single-day cases seen thus far this year.

Chicago is currently averaging more than 2,000 new cases per day, with a positivity rate of 8.3% — nearly double the 4.2% rate recorded by the Chicago Department of Public Health a week ago.

Those spiking metrics prompted Mayor Lori Lightfoot on Tuesday to implement new vaccine requirements for patrons going to bars, restaurants, music venues or gyms beginning Jan. 3.

Federal health officials announced Monday that the omicron variant of COVID-19 accounted for 73% of new infections last week, a nearly sixfold increase in only seven days.

The Centers for Disease Control and Prevention reported omicron's prevalence is even higher in some parts of the U.S., with the variant responsible for an estimated 90% of new infections in the industrial Midwest, the New York area, the Southeast and the Pacific Northwest.

The Associated Press contributed to this report.

Contact Matt Masterson: @ByMattMasterson | [email protected] | (773) 509-5431