Scientists Discover Omicron COVID-19 Variant Has a ‘Stealth Version’ That’s Harder to Detect With Testing

Scientists have discovered a "stealth version" of Omicron that's genetically different from the standard variant and harder to detect with COVID PCR testing.

December 8, 2021

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A new version of the Omicron COVID-19 variant has been discovered, with scientists saying it’s harder to detect using common PCR virus testing.

The Guardianreports that because the so-called “stealth Omicron” is more difficult to identify, its global transmission could go unnoticed. Researchers say this iteration doesn’t have a specific genetic change which COVID tests usually spot, and that it has other genetic features setting it apart.

This strain of Omicron can be detected using genomic testing and was recently found in Canada, Australia, and South Africa. Scientists are unsure how the stealth version will spread, and have identified it as BA.2, while the standard variant is BA.1.

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

Other researchers told the outlet the stealth variant is “worrying” and that public health experts are “missing a big part of the puzzle.” The original Omicron variant has been found in 19 states and more than 50 countries.

Omicron was first identified around Thanksgiving and could be twice as transmissible as Delta. Not much is known yet about just how infectious it is, and how effective vaccines are at curbing the strain.

On Wednesday, Pfizer said its COVID-19 booster shot could offer more protection against Omicron. Lab tests reveal boosters can raise the virus-fighting antibodies by 25-fold.

“Although two doses of the vaccine may still offer protection against severe disease caused by the Omicron strain, it’s clear from these preliminary data that protection is maximized with a third dose of our vaccine,” said Pfizer CEO Albert Bourla. “Ensuring as many people as possible are fully vaccinated with the first two dose series and a booster remains the best course of action to prevent the spread of COVID-19.”