"Stealth Omicron Detected in PCR Tests, Indistinguishable from Other Variants"

"Determining Omicron Without Additional Genome Testing Is Difficult"
"Omicron May Have Spread More Widely Than Expected"

[Image source=Reuters Yonhap News]

[Asia Economy Reporter Hyunwoo Lee] It has been reported that a so-called 'stealth' Omicron variant, which is not easily distinguishable from other variants in COVID-19 polymerase chain reaction (PCR) tests, has been discovered. As a result, concerns about the spread are growing, with the possibility that the Omicron variant has spread to more countries than previously confirmed.

According to the British daily The Guardian on the 7th (local time), scientists recently discovered a so-called 'stealth' Omicron variant that is difficult to distinguish from other variants in existing PCR tests due to certain specific genetic defects in the Omicron variant. The Guardian reported that this stealth Omicron variant was recently found in COVID-19 patient samples from South Africa, Australia, and Canada.

The Guardian stated that since the stealth Omicron variant was discovered only recently, it is not yet known whether it has the strong transmissibility like the existing Omicron variant. However, genetically, it is different from the existing Omicron variant, so its mode of activity may differ.

Accordingly, there are opinions that the Omicron variant (B.1.529) should be classified into two types: the existing BA.1 and the stealth variant BA.2. Professor Fran?ois Balloux of the Genetics Institute at University College London (UCL) explained, "Omicron has two lineages, BA.1 and BA.2," adding, "These two Omicron lineages may behave differently."

All COVID-19 viruses, including Omicron, are detected as COVID-19 viruses in PCR tests, but to accurately determine whether the variant is Omicron, additional genome testing is required. Some PCR testing tools could detect specific genetic defects of the Omicron variant and thus identify the variant as possibly Omicron. However, the stealth variant lacks these defects, making it difficult to determine whether it is Omicron through PCR testing.

Therefore, The Guardian warned that it cannot be ruled out that the Omicron variant has already spread to much wider regions beyond the countries or areas where it has been confirmed so far.