This is a reversal from an earlier trend, which saw Cook County, which includes Chicago, leading the state in coronavirus infections. Since March, Cook County has accounted for about 55% of the state’s Covid-19 cases. In the week prior to Aug. 17, Cook County accounted for 38% of the state’s new cases. In rural Effingham County, with a population of 34,000, cases recently surged from a few dozen in mid-July to 427 as of Sunday. By contrast, Cook County had a rate of about 100 cases per 100,000 residents for that week.

Source: Wall Street Journal August 25, 2020 13:29 UTC