Explained: What is Stealth Omicron and can it escape RT-PCR Covid-19 test?

As the battle against the Omicron strain of coronavirus rages across the world, the United Kingdom has issued a fresh warning.

Recall the World Health Organisation has noted that the Omicron variant has three sub-strains -- BA.1, BA.2, and BA.3. Reportedly, now the UK has said that the BA.2 sub-strain could cause a stronger wave across Europe.

The UK alarm is based on reports which claim the BA.2 strain can bypass the RTPCR test and therefore is being also dubbed as ‘stealth Omicron’.

The UK has designated BA.2 as a ‘variant under investigation’, which is a precursor to a strain being declared as a ‘variant of concern’.

According to researchers quoted by Fortune, even as the BA.2 sub-strain shares 32 strains with BA.1, there may be more than 28 unique mutations to it. Researchers say that BA.1 has a mutation — the deletion in the spike gene — that shows up on PCR tests, making the detection of Omicron easy. BA.2, on the other hand, does not have the same mutation which makes it difficult to detect.

Also Watch: WHO says end of Covid-19 pandemic in Europe ‘plausible’ after Omicron wave

While the BA.1 sub-strain is dominant among the Omicron infections reported across the world, the BA.2 sub-strain is spreading quickly. Apart from the UK and Denmark, cases of BA.2 sub-strain have been detected in Sweden, Norway, and India.