Experts warn of another Covid strain. Here's everything you need to know about the BA.2 subvariant

The omicron surge may be slowing in much of the world, but a new subvariant that scientists believe is even more contagious is on the rise.

The omicron subvariant, BA.2, appeared to be “steadily increasing” in prevalence and that BA.2 had now become dominant in several Asian countries, including China, India, Pakistan, Bangladesh and the Philippines. Denmark was the first nation to report that BA.2 had overtaken BA.1, the omicron version that first swept through the world.

However, the decline in the number of tests being conducted around the world is beginning to muddle the real picture, the World Health Organisation said.

"Among all subvariants, BA.2 is more transmissible than BA.1. However, there is no difference in terms of severity," Maria Van Kerkhova, COVID-19 Technical Lead at WHO said.

Should you be worried?
The BA.2 sub-variant shares many mutations with BA.1, but one major difference is the spike protein, according to the WHO. Some studies have shown that BA.2 sub-lineage has a higher propensity to spread among people and has the ability to infect people who have been fully vaccinated and/or previously infected by escaping from neutralising antibodies induced by vaccination or infection.

Dr Rajeev Jayadevan, Co-Chairman National IMA COVID Task Force, however, said there was nothing to be alarmed about. "It's not a new virus or strain. It's a sub-lineage and will be more transmissible than BA.1 but will not cause another surge."

The Japan study
The BA.2 subvariant is not only faster at spreading, but may also cause more severe disease, a lab study has suggested.

The yet-to-be peer-reviewed findings, recently posted on the preprint repository BioRxiv, show that the BA.2 sub variant may have features that make it as capable of causing serious illness as older coronavirus variants.

The study from the University of Tokyo also found that the BA.2 subvariant appeared to largely escape the immunity induced by COVID-19 vaccines.

"Neutralisation experiments show that the vaccine-induced humoral immunity fails to function against BA.2 like BA.1," the authors of the study said.

A new 'variant of concern'?
Meanwhile, a top epidemiologist urged the World Health Organisation to declare the BA.2 sub-strain of the Omicron a 'variant of concern' citing that it's capable of causing serious illness.

Taking to Twitter, epidemiologist Dr Eric Feigl-Ding on Sunday stressed that new lab experiments from Japan show that BA.2 may have features that make it as capable of causing serious illness as older variants – including Delta.

"BA.2 is seriously bad news. It’s both faster transmission than BA2 and if it’s truly more severe and as evasive against prior immunity including BA.1 old #Omicron immunity— then it’d be the worse of 4 worlds (sic)," he tweeted.