Stockholm, Mar 4 (IANS): The European Centre for Disease Prevention and Control (ECDC) has de-escalated three Covid-19 lineages from its list of 'variants of concern' (VOC).

Variants BA.2, BA.4 and BA.5 were de-escalated "as these parental lineages are no longer circulating", Xinhua news agency quoted the Centre as saying.

In November 2021, the ECDC categorized Omicron (B.1.1.529) as "the most highly mutated SARS-CoV-2 variant to-date".

It quickly became dominant globally and resulted in a surge of Covid-19 cases.

Subsequently, a number of Omicron sublineages have emerged (BA.1, BA.2, BA.3, BA.4 and BA.5).

Currently, the BA.2 and BA.5 descendent variants are circulating, whose properties differ from their parental lineages and which require individual assessment, the ECDC said.

The ECDC currently lists the most prominent of these under the categories of "variant of interest" and "variant under monitoring".

The absence of SARS-CoV-2 variants categorized as "of concern" reflects the current stable epidemiological situation in the European Union and the European Economic Area, the ECDC said, emphasizing, however, that "it does not signal the end of the threat posed by SARS-CoV-2 and possible future variants that may emerge".

The centre encourages countries to remain vigilant by reinforcing their surveillance systems, sequencing capacities and reporting practices.