Should you be worried about transmissible subvariant 'stealth Omicron' of COVID-19? All you need to know

The U.K. Health and Security Agency (UKHSA) announced Friday it is investigating a sub-lineage of the omicron coronavirus variant—known as BA.2 and nicknamed by some scientists as “stealth omicron”—that appears to be outpacing other forms of the variant around the world and is raising fears of an even more transmissible strain of the virus.

Why "Stealth Omicron"? Given the speed at which it is outpacing other Omicron subvariants, it is sparking fears that a more transmissible strain of coronavirus is actively spreading through the community.

According to World Health Organization (WHO), the Omicron variant has three sub-strains: BA.1, BA.2 and BA.3. It further said that as many as 99 per cent of the cases sequenced were found to be containing the BA.1 sub-strain.

The WHO further said that the knowledge about B.1.1.529 is still developing, but this lineage is more diverse.

Apart from the UK, the BA.2 has been found in Denmark, Norway and Sweden. Scientists in France and India have also warned about the quick spread of the BA.2 sub-variant, which is expected to outpace other Omicron strains.

While cases are low in the U.K., BA.2 accounts for nearly half (45%) of Danish Covid-19 cases, according to Denmark’s Statens Serum Institut (SSI), part of its ministry of health, a jump from just 20% in the last week of 2021.

Researchers have pointed to the probable reason why the new sub-strain is expected to become the dominant cause of Covid-19 in months to come.

Vipin M Vashishtha, Member of WHO’s Vaccine Safety Net, said on Twitter that BA.2 shares 32 mutations with BA.1 but also has 28 unique mutations of its own.

In recent weeks, many experts have claimed that the sub-strain does show up on PCR tests. “BA.2 _is_ detectable by PCR, these news reports are totally wrong. Depending on the PCR test used it may not look like BA.1 (the other Omicron). But it will still give a positive result. Frustrating to see falsehood about non-detectability still around,” Cornelius Roemer, a computational biologist at Switzerland's University of Basel, said on Twitter.