Though some experts believe that the BA.1 sub-strain of Omicron is capable of escaping the RT-PCR, at the moment, it is the only gold standard test available, said Dr Ashutosh Shukla, Senior Director – Internal Medicine & Medical Advisor at Max Hospital in Gurugram.
In a conversation with Livemint, Dr Shukla spoke about the new subvariant, BA.2 that has been found in a substantial fraction in the country.
Edited excerpts: What is ‘stealth Omicron’?
Stealth Omicron is the name given to the new variant of omicron, pertaining to the fact that it lacks the deletion of a spike gene (protein responsible for mutation and is contagious).
It is known as the stealth variant because it can be detected only through genome sequencing and its one of the sub lineages. While Omicron has three variants BA.1, BA.2 and BA.3, BA.2 (stealth omicron) has been recently reported to be a dominant strain across many European and Asian countries, lately.
In fact almost 50% of the active cases in countries like Denmark have been reported to be of this sub-strain.
Can the sub-strain of the Omicron variant escape RT-PCR test?
The RT- PCR tests done in the labs detect the spike gene (a protein that showcases new variations than the old virus) through sequencing. Though various experts believe that the BA.1 sub-strain may sometimes escape the RT-PCR test, but as of now, that is the only gold standard tests available and do not pose any difference in any of the mutated variants.
According to the reports by various experts and radiologists worldwide, the current testing kits are designed with high sensitivity and pick up rate to detect all the variants.
Is there any evidence of its rapid spread?
While genome sequencing is the only way to identify the exact variant, this procedure may take up to one week. Yet there is a kind of fear that the stealth variant is emerging as a ‘variation of concern’ among many countries.
Yet there has been no evidence as of now about its rapid spread, and experts also believe that it is unlikely to be turned into a pandemic. Also, that vaccines are unlikely to be ineffective against this variant.