Scientists find stealth version of Omicron, say tracking variant could be difficult

Scientists say that they have found another version of the Omicron variant, which cannot be identified by RT-PCR tests. Public health officials across the world have been using the RT-PCR tests as a proxy to identify the presence of Omicron in individuals without the need for more time-consuming genetic sequencing.

The Omicron variant has over 50 mutations in comparison to the ‘wild’ SARS CoV-2 virus and some of the mutations resulted in the absence of some amino acids on the spike protein of the virus. One of these amino acids includes the S-gene target, which is one of the three targets of the PCR test, going missing on the virus. While RT-PCR tests would still be effective in identifying cases of COVID-19, the missing S-gene target could be used as a proxy to identify cases of the Omicron variant. Previously the Alpha variant of the virus could also be identified by the same proxy method.

The stealth version of the variant however does not have the same genetic change as the usual Omicron variant and thus doesn’t have the missing S-gene target. The new version of the Omicron was spotted among genomic samples gathered from South Africa, Australia and Canada in recent days. According to News.com, the Queensland government in Australia has confirmed detecting a case of ‘stealth strain’.

Scientists say that the new Omicron version is genetically distinct and may have different behaviour than the normal variant, which itself is still being studied upon. The discovery of the new version has led to a new subdivision within the Omicron lineage. B.1.1.529 BA.1 has been designated as the standard Omicron while BA.2 has been designated as the stealthier version. Though scientists don’t yet know how this new version emerged.

“There are two lineages within Omicron, BA.1 and BA.2, that are quite differentiated genetically,” Prof Francois Balloux, the director of the University College London Genetics Institute was quoted as saying by the Guardian. The two lineages may behave differently, according to Prof Balloux.

While genomic sequencing can still identify the cases of Omicron variant, authorities had been relying on the proxy method. Authorities have been trying to stem the increase in the number of cases as eligible individuals in numerous countries are being encouraged to get booster shots administered. Official data from the United Kingdom suggests that the variant is already infecting more than 1,000 individuals each day, as early data indicates that the variant is much more transmissible than even the Delta variant.

Reports from South Africa also suggest while more infectious, the variant causes COVID-19 with less severe symptoms than Delta. Though top health officials like Dr Anthony Fauci, the Chief Medical Advisor to President Joe Biden and the director of the National Institute of Allergy and Infectious Diseases, have still cautioned against premature optimism. CNBCTV18