(Patty Wetli / WTTW News)

The threat of COVID-19 rose across Chicago and Cook County Thursday, as federal officials moved the warning level to “medium” after 50 days at “low,” according to Centers for Disease Control data.

Dr. Allison Arwady, the commissioner of the Chicago Department of Public Health, has been warning for weeks that COVID-19 was likely to surge once colder weather settled over Chicago for the duration, forcing people indoors.

The elevated risk means public health officials once again recommend that residents wear masks indoors and on public transportation.

All Chicagoans eligible for a COVID-19 booster designed to fight the omicron variant of the virus and a flu vaccine should be inoculated as soon as possible, Arwady said.

“Families will be traveling and gathering indoors for the holidays, and I worry about that increased circulation of COVID-19 and flu, and especially the possibility of severe outcomes for those who remain unvaccinated or not up to date,” Arwady said in a statement.

Just 13% of eligible Chicagoans have received a dose of the reformulated COVID-19 vaccine, which is the best way to prevent serious illness from COVID-19, according to city officials. White Chicagoans are more likely to have gotten the bivalent booster than Black or Latino Chicagoans — making them far more vulnerable to serious illness, officials said.

COVID-19 has killed 7,920 Chicagoans since March 2020 — 87% of those who died were unvaccinated, according to city data.

During the past seven days, an average of 27 people have been hospitalized each day in Chicago from COVID-19 essentially unchanged since a week ago, according to city data.

Cook County now has 113 confirmed cases of COVID-19 per 100,000 residents, but hospitalizations rose slightly across the Chicagoland region prompting federal officials to raise the risk level.

Cook County now has 10.3 new COVID-19 hospital admissions per 100,000 residents during a seven-day period, according to data released by the CDC.

Residents of regions face a low risk of COVID-19 if there is a case rate of less than 200 confirmed cases of COVID-19 per 100,000 residents and fewer than 10 new COVID-19 hospital admissions per 100,000 residents.

According to the CDC, 3.6% of staffed hospital beds in Cook County are in use by COVID-19 patients on average during the past seven days.

The city of Chicago has 7.1 new COVID-19 hospital admissions per 100,000 during a seven-day period and a case rate of 107 confirmed cases of COVID-19 per 100,000 residents, according to Chicago Department of Public Health data released Thursday.

In Chicago, 3.2% of staffed hospital beds are in use by COVID-19 patients, according to CDPH data released Thursday. 

Federal health officials measure the strain facing hospitals from COVID-19 by the number of new hospital admissions per 100,000 residents during a seven-day period and the percent of staffed hospital beds in use by COVID-19 patients on average during the past seven days.

Contact Heather Cherone: @HeatherCherone | (773) 569-1863 | [email protected]