1st 'Stealth Omicron' Case Found In Illinois
ILLINOIS — "Stealth omicron" — a subvariant of the highly contagious omicron COVID-19 variant — has been found in an Illinois patient, Northwestern Medicine announced Monday. The case comes as health officials said the surge of omicron cases appeared to have been winding down in Illinois.
Northwestern Medicine said the case was detected this weekend by the Northwestern Medicine’s Center for Pathogen Genomics and Microbial Evolution (CPGME).
Officials said the patient was tested for COVID-19 on Jan. 18 but did not say where the patient lives in Illinois.
"Now the question is whether the new subvariant will extend the tail of cases infected with omicron," Ramon Lorenzo-Redondo, the bioinformatics director at CPGME, part of Northwestern University Feinberg School of Medicine, said in a news release.
Although omicron cases are declining in much of the U.S., Northwestern Medicine said case counts have plateaued in countries where "stealth omicron," known as BA.2, is more prevalent.
That means stealth omicron could extend the current COVID-19 surge, even as some hospitals loosen regulations as case counts drop.
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"If BA.2 follows the same pattern in the U.S. as observed in countries like the United Kingdom, Denmark or India, we could observe a slowing of the current decline in new cases," Lorenzo-Redondo said. "In this case, the number of new cases could stabilize for a while before starting to decrease again."
But, he said, it's too soon to know for sure since there are still so few stealth omicron cases in the U.S.
The subvariant's mutations mean it could be even more transmissible, said Judd Hultquist, associate director of CPGME.
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"It is unclear if the arrival of this new variant will result in a surge of local cases, but it is an important reminder that we are still in the middle of an ongoing pandemic," Hultquist said. "Vaccinations, booster shots and the proper use of face masks are still the best ways to protect yourself and your loved ones from this virus."
Northwestern Medicine said preliminary data shows being fully vaccinated and receiving a booster are similarly effective against both omicron and "stealth omicron."
So far, the subvariant has been found in more than 40 countries.
While cases in other countries have shown that BA.2 may be more transmissible than the omicron variant, there is no data yet showing it may cause more severe illness, CPGME director Dr. Egon Ozer said.
But omicron has been shown to be resistant to some antibody treatments.
"Understanding which variants are circulating in a community is critical to inform the best practices in public health and clinical care," Hultquist said in a news release. "For example, the omicron variant has been found to be resistant to a couple different monoclonal antibody treatments, which now can no longer be considered part of our effective therapeutic toolbox."
The rise of omicron signaled a potential end to a wave of delta variant cases in Illinois.
From the end of November through the end of December, the population of viruses shifted from nearly 100 percent delta to nearly 100 percent omicron in Chicago, a remarkable change in a very short period of time, Hultquist said.
This article originally appeared on the Chicago Patch
