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VERIFY: Will a COVID-19 test tell you if you have the omicron variant?

You can't identify the omicron variant with just a simple PCR or antigen test. Here's a look into the process to find variants.

WASHINGTON — The Omicron variant of COVID-19 has been identified in more than 20 countries, now including the United States. Research is still ongoing to determine its severity and transmissibility, but it's still top of mind for those tapped into the many ebbs and flows of the pandemic. 

In the meantime, scientists around the country are working to identify any possible cases of Omicron that might already be here. The process is a bit complex, so Verify is breaking down the essentials.

OUR SOURCES

  • Dr. William Moss, Vaccines Expert at Johns Hopkins Bloomberg School of Public Health
  • Dr. Gigi Gronvall, Senior Scholar and COVID-19 testing expert at the Johns Hopkins Center for Health Security  
  • Dr. Matt Frieman, Professor of microbiology and immunology at the University of Maryland School of Medicine
  • Dr. Glenn Wortmann, Infectious Diseases Specialist at MedStar Washington Hospital Center
  • The Centers for Disease Control and Prevention

Can a COVID-19 test, on its own, tell you if you have the Omicron variant?

This is false.

Rapid antigen tests are not able to differentiate between variants. Those tests will only be able to tell you whether or not you are currently infected with SARS-CoV-2.

PCR tests, which are much more common, on their own cannot tell you which variant of COVID-19 you have. However, Dr. Gronvall explained that a PCR can give scientists a clue as to whether one might be dealing with Omicron.

"It looks for three different parts of the virus, and one of those parts is not the same in Omicron as in Delta," she said. "There will be one target that the test looks for that's not going to be present in Omicron. It's still going to be able to tell you that you're positive for SARS-CoV-2, though."

One of the things a PCR test looks for is the specific spike protein unique to the COVID-19 virus. But Omicron has mutated enough that the spike protein is seemingly unrecognizable to the PCR test. So while the result still shows up positive on the other sections of a test, the negative spike protein throws up a red flag to send it off for further testing.

RELATED: As omicron comes into focus, what is a 'variant of concern?'

How is a variant identified?

This involves the complex process of genomic sequencing. The genetic makeups of all variants that have been identified are kept track of in databases shared worldwide. That red-flagged positive test then gets sent to a lab to have its RNA extracted, analyzed and matched with other variants.

"So it's removed, it is amplified, and then sequenced in a variety of ways," Dr. Frieman explained. "And then the whole sequence of that virus that was in your nose is now in your computer."

Dr. Wortmann told Verify that sequencing is a lot like a matching activity for RNA.

"If you think of little boxcars on a train, there are 30,000 of those boxcars with the RNA virus," he said. "Then with computers, they compare them to known trains. And they say, 'is this the exact same sequence of the Delta virus?' And they say, 'Yes, it is. So it's another Delta virus.' Or, is it something different?"

That's how the Omicron variant was originally identified by scientists in South Africa—they found an RNA sequence that no one had spotted yet. Now, labs in the U.S. are tasked with searching for that same variant RNA to identify cases of Omicron. Right now, only about 1% of positive COVID-19 tests are sent out for sequencing.

If you test positive for COVID-19, will you ever know which variant you have?

Our experts all said that's highly unlikely. 

"Generally speaking, unless you're in some kind of special research trial, you're not going to know if you're infected with one variant or another," Frieman said.

But the bottom line, Dr. Gronvall stressed, is that no matter the variant, you've still got COVID-19, and that's what's most important.

"It does not matter if you have Omicron or Delta," she said. "If there is a therapy that ends up working for one version versus another, then that's something we can talk about, but at this point, it's information that is not really that important for the individual."

However, Omicron cases will be reported back to state and local health departments to track spread.

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