Almost Every County Near Chicago Seeing 'Substantial' COVID Cases

KANKAKEE, IL — Every county in the Chicago area is now seeing what the Centers for Disease Control and Prevention are calling "substantial" transmission of the coronavirus — except for one.

Kankakee County is still classified as moderate in terms of transmission. For the rest of Chicagoland, mask mandates and updated COVID-19 restrictions could be on the horizon and are already encouraged in many state buildings, Gov. J.B. Pritzker said last week.

Last week, the CDC updated its guidance to recommend people in regions where the risk of contracting COVID-19 is high to wear a mask, even those who are fully vaccinated. The new guidance follows the agency's earlier optimism when it said fully vaccinated people could choose not to wear a mask in most public settings.

"While data continues to show the effectiveness of the three COVID-19 vaccines currently authorized in the U.S., including against the Delta variant, we are still seeing the virus rapidly spread among the unvaccinated," Illinois Department of Public Health Director Dr. Ngozi Ezike said in a statement.

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According to state health officials, state entities such as public schools K-12th grade will follow the CDC's guidelines and require masks for students and staff this fall.

Despite Kankakee County's slightly lower transmission rate, almost all of Illinois' counties still fall into one of the top tiers of transmission risk, with six counties labeled as moderate and only Henderson County on the Iowa border labeled as low.

The CDC determines the categories using community data on the number of new cases per 100,000 residents and the percent of positive coronavirus tests in the past calendar week. Hospitalizations are measured separately, officials said.

A county with 50 to 100 cases per 100,000 residents over a weeklong period will be placed in the substantial transmission category. High transmission requires 100 or more cases per 100,000 residents or a positivity rate of 10 percent. Substantial and high transmission areas are where the CDC strongly recommends even vaccinated individuals wear a mask.

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State health officials said the CDC's data on the delta variant show it is almost twice as contagious as other coronavirus variants.

Kankakee County Department of Public Health did not immediately respond to requests for comment.