Just as governments across Europe have voiced their intentions to ease COVID-19-related restrictions, the spectre of another wave of the virus is sparking concern among the scientific community.
Omicron subvariant BA.2, which is being dubbed with the moniker "Stealth Omicron," appears to be gaining ground in certain parts of the world, including Denmark and the UK.
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.
The UK Health Security Agency designated the BA.2 as a variant under investigation on Friday while emphasising that current case rates are very low.
The agency said they will undertake further analyses.
"53 sequences of the BA.2 sub-lineage of Omicron had been identified in the United Kingdom," it said in a statement.
"This sub-lineage, which was designated by Pangolin on 6 December 2021, does not have the spike gene deletion at 69-70 that causes S-gene target failure (SGTF), which has previously been used as a proxy to detect cases of Omicron. UKHSA are continuing to monitor data on the BA.2 sub-lineage closely".
Dr Meera Chand, Incident Director of the UKHSA said "It is the nature of viruses to evolve and mutate, so it's to be expected that we will continue to see new variants emerge as the pandemic goes on.
“Our continued genomic surveillance allows us to detect them and assess whether they are significant".
Omicron, which is also referred to as B.1.1.529, has three main substrains, BA.1, BA.2, and BA.3, according to the World Health Organization (WHO).
Up until now, it has been BA.1 that has been dominating with the WHO estimating it makes up a large majority of all Omicron cases.
However, in some places, the BA.2 has begun to spread faster.
In Denmark, it now makes up almost half of all Omicron cases. Other countries such as the UK, Norway and Sweden are also experiencing an increase in BA.2 cases, although not to the same extent.
"Initial analysis shows no differences in hospitalisations for BA.2 compared to BA.1,” said Denmark’s Statens Serum Institut, a government-run infectious disease research center, in a statement on Thursday.
"Analyses regarding infectiousness and vaccine efficiency etc. are ongoing, including attempts to cultivate BA.2 in order to perform antibody neutralization studies. It is expected that vaccines also have an effect against severe illness upon BA.2 infection".