Less than one month after omicron was confirmed in Chicago, it made up nearly all COVID-19 cases in one city report
- Oops!Something went wrong.Please try again later.
Within one month of its identification in Chicago, the omicron variant of the coronavirus has quickly become the dominant strain in the city, according to a report from the Chicago Department of Public Health.
The first confirmed case of omicron in a Chicago resident was announced Dec. 7. By January, the variant made up more than 90% of the COVID-19 samples analyzed by a Rush University Medical Center Lab, according to the city’s public health department.
The speed of omicron’s rise is quicker than the rise of previous variants of the virus, said Hannah Barbian, a Rush University Medical Center virologist who worked on the testing. The findings in Chicago are in line with the trajectory of omicron in cities across the U.S., she said.
“I think this has shown just how quickly the virus spreads,” she said. “We have to remain vigilant in wearing our masks in public indoor places, and some of the things we’ve been doing the whole pandemic will continue to be super useful in trying to slow the spread of omicron.”
The findings are the result of 889 samples collected between Dec. 1 and Jan. 2 and analyzed by the Regional Innovative Public Health Laboratory, a partnership between Rush and the city’s public health department. The lab collected samples from 12 hospitals across the city.
Another organization, the Center for Pathogen Genomics and Microbial Evolution at Northwestern University, analyzed 299 samples, and reached similar conclusions about the rise of omicron, according to the department of public health.
Both findings are in line with Centers for Disease Control and Prevention estimates for the upper Midwest region that includes Illinois, which projected omicron was making up nearly 94% of cases in the area.
The rise in omicron came as COVID-19 cases in Chicago ticked sharply upward. On Dec. 1, the average positivity rate in the city was 4%, and by Jan. 1 it was 21%.
The variant’s prevalence is probably both because it is easily transmissible and it likely can, to some extent, evade immunity gained from vaccines or previously having the virus, Barbian said. But vaccines remain effective, especially at preventing severe cases of COVID-19, and are particularly important to keep people out of hospitals as they are becoming overburdened with patients, she said.
It’s also important to keep COVID-19 numbers under control because the more it spreads, the more chances there are for new variants to crop up, she said.
“With uncontrolled COVID numbers, there’s always chances for COVID to keep evolving,” she said.
