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VERIFY: How do health officials know if someone has the omicron variant or another COVID-19 variant?

The usual PCR test only shows if someone is positive or negative for COVID-19. How is the variant type determined?

CHARLOTTE, N.C. — The new omicron COVID-19 variant is confirmed in more than 20 states, but it is just the latest of several variants health officials have tracked since the pandemic started.

The new variant's emergence is leading some to wonder: How do scientists know if a certain case is omicron, delta, or another type of coronavirus?

The Question

Gale G. from Hickory, North Carolina, reached out to the WCNC Charlotte Verify team with the following question: 

How do I know which variant I have when testing only shows a positive or negative result?


The Answer

"Genomic sequencing is the only test that would differentiate whether a person had delta versus another variant of the COVID-19 virus," Traxler said.

Traxler said the genomic sequencing process is only applied to a relatively small share of positive test samples, and those samples are chosen strategically to get the best picture of variant proportions in the community.

"The goal of surveillance is not to sequence every single positive test. It's to make sure we're getting a representative sample -- so not just looking at the number performed, but making sure that they're representative of the positive specimens in the state from all different angles," Traxler said.

Since variants of viruses happen when mutations happen, certain laboratories around the country are responsible for sequencing the COVID-19 samples, getting down to the genetic level, and seeing which mutations each sample has. Scientists can then determine which variant they are seeing.

According to the CDC, the most recent four weeks of sequencing data shows nearly 2,300 sequenced samples taken from North Carolina alone. 99.2% showed the delta variant, reinforcing that the delta variant is still dominant, by far.

Contact Vanessa Ruffes at vruffes@wcnc.com and follow her on FacebookTwitter and Instagram

VERIFY is dedicated to helping the public distinguish between true and false information. The VERIFY team, with help from questions submitted by the audience, tracks the spread of stories or claims that need clarification or correction. Have something you want VERIFIED? Text us at 704-329-3600 or visit /verify.

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