© Christophe Archambault/AFP/Getty ImagesResearchers have discovered a new version of the Omicron coronavirus variant that is more difficult to detect through PCR testing.
Scientists have recently reported finding a new version of the Omicron coronavirus variant that is more difficult to identify using standard PCR coronavirus testing, leading experts to fear it may be spreading less noticeably around the world.

The new version has been dubbed "stealth Omicron" by some researchers because it lacks a particular genetic change that allows it to be easily detected in the lab-based COVID-19 tests, according to a report from The Guardian.

Researchers have said that this new version has other genetic features to differentiate itself from the standard Omicron variant. While it can still be detected as Omicron through genomic testing, studies have found that it is not as easily flagged by routine PCR tests that are used around the world to measure how quickly the virus is spreading, according to the news outlet.

This new version of Omicron was recently discovered among coronavirus genomes from South Africa, Australia and Canada, The Guardian reported. So far, researchers have said it is too early to tell whether the new form of Omicron, identified as BA.2, will spread in the same way as the standard Omicron variant, known as BA.1.

"There are two lineages within Omicron, BA.1 and BA.2 differentiated genetically," professor Francois Balloux, director of the University College London Genetics Institute, told The Guardian. "The two lineages may behave differently."

Others told the news outlet that having two versions of a variant in quick succession with shared mutations is "worrying," or may suggest that public health experts are "missing a big piece of the puzzle."

The finding comes just a week after the Omicron variant was first discovered in the U.S. Since then, nearly half of U.S. states have reported cases of Omicron, which has been deemed a variant of concern by the World Health Organization (WHO) after it was initially detected in South Africa last month.

Researchers are still discovering information about the variant, but early data has suggested that it is twice as transmissible as Delta โ€” currently the dominant variant in the U.S. โ€” and that it could be more effective at evading immunity due to its high level of mutations.

On Tuesday, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said that while the Omicron variant may be able to infect more people, he does not believe it will cause as many deaths as Delta.

Fauci told Agence France-Presse that Omicron "almost certainly is not more severe than Delta," but added that the "worst-case scenario," would be if the variant is determined to be highly transmissible and cause severe disease.

The infectious disease expert predicted that it will still take another couple of weeks for researchers to analyze the outcome of Omicron cases.

"As we get more infections throughout the rest of the world, it might take longer to see what's the level of severity," Fauci said.