The World Health Organization on Friday classified the B.1.1.529 strain of the coronavirus as a “variant of concern” and named it “Omicron”.

A “variant of concern” has the highest threat perception among other coronavirus variants because of its increased transmissibility, infectivity, or resistance to vaccines. The threat perception for a “variant of interest” is comparatively lower.

“This variant [B.1.1.529] has a large number of mutations, some of which are concerning,” the global health body said. “Preliminary evidence suggests an increased risk of reinfection with this variant, as compared to other VOCs [variants of concern].”

The number of cases of the Omicron variant appeared to be increasing in almost all provinces in South Africa, the WHO said.

The global health body asked countries to “enhance surveillance and sequencing efforts to better understand circulating SARS-CoV-2 variants”. It also asked governments to “submit complete genome sequences and associated metadata to a publicly available database”.

The WHO urged countries to report the first cases or clusters linked to the Omicron variant. It also added that field investigations and laboratory analysis should be conducted “where capacity exists and in coordination with the international community”.

The world body appealed to the public to take steps to reduce the risk of contracting Covid-19 and follow all protocol, including vaccination.

The B.1.1.529 variant was first detected in South Africa on November 24. The world health body said that the country’s epidemiological situation has been characterised by three peaks – “the latest of which was predominantly the Delta variant”.

“In recent weeks, infections have increased steeply, coinciding with the detection of B.1.1.529 variant,” the WHO said about the situation in South Africa. “The first known confirmed B.1.1.529 infection was from a specimen collected on 9 November 2021.”

Several countries have imposed restrictions on travel due to the emergence of the Omicron variant.

Members of the European Union’s crisis response panel have agreed on the need to impose temporary restrictions on all travel to the region from southern Africa.

The United Kingdom has already announced a ban on six south African countries beginning from Friday. The countries are South Africa, Namibia, Lesotho, Eswatini, Zimbabwe and Botswana.

Germany, France Italy, Singapore and Israel too have announced a ban on travel from the region.

United States President Joe Biden said on Friday that the country will ban most travellers from eight countries in southern Africa starting from November 29, Reuters reported. The restrictions will not apply to Americans and lawful permanent residents of the country.

India has advised its states and Union Territories to take note of the new variant and asked them to ensure rigorous screening of international travellers.