What is ‘stealth omicron’ and How Worried Should We Be?

Chicago natives may be exhausted to hear anything related to a new variant or even sub-variant of COVID-19, which has already killed hundreds of thousands of Americans, sickened many others and caused two years of disruption.

A post-holiday surge of the omicron variant already has stressed hospitals across the country, bringing them to their breaking points. It’s also made many who are weary of coronavirus restrictions on their lives even more so. Now the World Health Organization is warning a new version of omicron is being seen in more countries and has said investigating it should be prioritized.

So how big a worry is the so-called stealth omicron, which some experts have said could be better at evading detection in testing, giving it its nickname?

Dr. Allison Arwady, commissioner of the Chicago Department of Public Health, mentioned it in a news conference Tuesday, noting the omicron subvariant is something officials are watching.

“We’re keeping an eye on it. There’s nothing that we’ve seen at this point that is raising a high level of concern, but please rest assured we’re watching it,” she said.

The good news? Stealth omicron may be surprising to Americans exhausted by COVID-19′s twists and turns, but it’s already been on the radar for local scientists.

Dr. Hannah Barbian, a virologist at Rush University Medical Center, has been tracking various variants, including this one, which is officially known as BA.2. She said scientists aren’t using the “stealth omicron” moniker, and said she is awaiting more data from Europe, where it has spread the most.

Here’s what Chicago experts had to say about what is known, and why not to panic.

The World Health Organization monitors variants, and within omicron, scientists are watching sublineages, BA.1 and BA.2. The first is the original omicron variant and remains the most common in the U.S., and the second is the new version.

most changes don’t impact the virus much, but some do affect how easily it spreads or the severity of the disease. That’s what experts want to ascertain as more variants surface.

Variants are separated and defined as having mutations that are suspected or known to be significantly different from the original strain, or variants of concern, which have hallmarks like spreading more rapidly, causing more severe disease or escaping the body’s immune response. Right now, omicron is a variant of concern.

Denmark and Norway have both logged cases, and most eyes seem to be on Denmark.

Ramon Lorenzo Redondo, an assistant professor of infectious disease medicine at Northwestern Medicine’s Feinberg School of Medicine, said it is too soon to tell if this subvariant is something that happens to be circulating more in Denmark or if it is more contagious. Even if cases are rising, he emphasized those cases were few to begin with and continue to be a small portion of the world’s overall omicron cases.

Although some cases have been found in Texas, none have been identified in Chicago.

“We have the ability to detect that subvariant here in Chicago, just like we do other types of subvariants, and I’ve not seen anything at this point that gives me a lot of concern at all,” Arwady said.

Barbian said scientists sometimes use a specific type of PCR test to assess the genotype of the virus, and that while using this test, it can be hard to determine whether the virus is the delta variant, or BA.2. But, she emphasized, this is not a commonly used diagnostic test.

“So if you go in for a COVID test anywhere, if you get a PCR test or an antigen test, that’s still going to detect this variant,” she said.

It’s too soon to tell if this is more severe or more contagious.

That doesn’t mean it will be; it simply means studying variants is always a balancing act between alerting the public to potential new strains while knowing we won’t immediately have enough data to thoroughly assess them.

That said, scientists will be watching data from Europe closely.

“I think the really important message is even though it’s being called the stealth variant, it still is detected,” she said. “We know with omicron now that getting vaccinated, getting boosted, really helps prevent severe infection, so that’s still the best thing you can do.”