New Delhi, Nov 29, : Omicron is the newly-detected Covid variant that has stoked fears about vaccine resistance.It is the most mutated virus version found so far. Indian health experts claimed Monday that the current diagnostics tools may not be able to detect the Omicron Covid variant.
The SARS-CoV-2 virus mutated in the two years since the Covid-19 pandemic.
This has led to genetic variation in the number of circulating viruses.Due to the inherent design differences between each test, viral mutations can affect all types of tests: serology, antigen, and molecular.
Last week, the World Health Organization classified the latest variant of SARS-CoV-2 virus, B.1.1.529, as Omicron, a “Variant of Concern” (VOC).This means that it could be more contagious or more virulent, and can evade public health measures, vaccines, and therapeutics.
According to the global health agency, the Omicron variant is classified under the S gene.
The spike glycoprotein of SARS CoV-2 is encoded by the S gene.It is used to detect the presence and severity of Covid-19.
“Most of the ICMR-approved RTPCR kits used in India target the Rd Rp, E and N genes.The latest variant has seen mutations in the S gene.
Common RT-PCR kits will identify positive and negative results, but they will not be able identify if the positive result was due to the mutation of the S gene,” Arjun Dang CEO, Dr Dangs Lab told IANS.
“Based on the data, RTPCR kits for S gene, particularly the Taqpath kit by Thermofisher will be able screen the new variant,” stated Veena Menon Consultant, Clinical Virology, Amrita Hospital.
Researchers discovered B.1.1.529 from Botswana’s genome-sequencing data.This variant stands out because it contains more that 30 changes to the spike protein, the SARS-CoV-2 protein which recognises host cells and is the primary target of the body’s immune responses.
Some mutations are alarming among the many.
The WHO stated that preliminary evidence suggests that this variant is more likely to cause reinfection than other VOCs.
The global health body said that the current SARS-CoV-2 DNA PCR diagnostics are still able to detect the new variant.
According to the WHO statement, “Several labs have indicated that one of the target genes for a widely used PCR test is not detected (called S Gene Dropout or S Gene Target Failure).This test can therefore be used for this variant as a marker, pending sequencing confirmation.”
Gene dropout can be a situation in which a mutation occurs in a part of the virus’ DNA that has been tested by PCR.The sample could result in gene “dropout”.
It said that the variant was detected faster than other surges in infection.This suggests that it may have a growth advantage.
“But mutations in S genes are more common, which can affect not only virus infection but also detection.This was also observed in the cases of Alpha and Beta variants.
Menon stated that the new variant shows a mutation/deletion that is similar to the Alpha variant.Therefore, S gene drop out test (a PCR method) can be used as an initial screening tool.
Monday’s announcement by Thermo Fisher Scientific that its Covid-19 diagnostic test, TaqPath Covid-19 assays — also approved by US FDA — can accurately detect Omicron.
The company stated in a statement that it could report accurate results even if one of its gene targets is affected by a mutation.
According to Mark Stevenson (Chief Operating Officer at Thermo Fisher Scientific), “it can also serve as a proxy of the [Omicron] variation.”
Omicron was first discovered in Botswana, South Africa, and has since spread to other European countries, including Belgium, France, the UK, and Canada.
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