The World Health Organization has declared the recently-discovered B.1.1.529 strain of Covid-19, first detected in southern Africa, to be a variant of concern, and have renamed it Omicron.
The classification puts Omicron into the most-troubling category of Covid-19 variants, along with the globally-dominant Delta, and others Alpha, Beta and Gamma.
The European Centre for Disease Prevention and Control has warned that the Omicron variant poses a “high to very high” risk to Europe.
The ECDC noted in a threat assessment report that there was still “considerable uncertainty related to the transmissibility, vaccine effectiveness, risk for reinfections and other properties of the Omicron variant.”
However, the overall risk that Omicron posed to the European Union and European Economic Area (Iceland, Liechtenstein and Norway) was “high to very high.”
Given the possibility that current vaccines may not protect against the variant, and the fact that it may be more transmissible, “we assess the probability of further introduction and community spread in the EU/EEA as high,” it said.
Nations have rushed to ban flights to slow the spread of Omicron, while stock markets and oil prices plunged on fears surrounding the variant, potentially dealing a heavy blow to the global economic recovery.
“Based on the evidence presented indicative of a detrimental change in Covid-19 epidemiology… the WHO has designated B.1.1.529 as a variant of concern (VOC), named Omicron,” the UN health agency said in a statement.
The WHO said it could take several weeks to complete studies of Omicron to see if there are any changes in transmissibility, severity or implications for Covid vaccines, tests and treatments.
The change in classification came after a quickly-assembled virtual meeting of the WHO’s Technical Advisory Group on SARS-CoV-2 Virus Evolution.
The variant was first reported to the WHO from South Africa on Wednesday.
The first known confirmed Omicron infection was from a specimen collected on 9 November. In recent weeks, infections in South Africa have increased steeply, coinciding with the detection.
“This variant has a large number of mutations, some of which are concerning,” the WHO said, pointing to worrying characteristics.
“Preliminary evidence suggests an increased risk of reinfection with this variant, as compared to other VOCs.”
It said the number of Omicron cases appeared to be increasing in almost all provinces of South Africa.