The U.N. health agency recognized the strain, first referred to as lineage B.1.1.529, as a variant of concern.
Health experts are deeply concerned about the transmissibility of the omicron variant given that it has an unusual constellation of mutations and a profile that is different from other variants of concern.
“Omicron, B.1.1.529, is named as a variant of concern because it has some concerning properties,” Maria Van Kerkhove, the WHO’s technical lead on Covid-19, said in a video published on Twitter. “This variant has a large number of mutations, and some of these mutations have some worrying characteristics.”
Experts fear that the sharp upswing of Covid cases in South Africa’s Gauteng province — where the heavily mutated strain of the virus was first identified — could mean it has greater potential to escape prior immunity than other variants. The number of omicron cases “appears to be increasing” in almost all of South Africa’s provinces, the WHO reported.
The organization only labels Covid strains as variants of concern when they’re more transmissible, more virulent or more adept at eluding public health measures, including vaccines and therapeutics. Data presented at a briefing Thursday hosted by South Africa’s Department of Health indicates that some of omicron’s mutations are connected with improved antibody resistance, which could reduce the protection offered by vaccines.
Certain mutations could also make omicron more contagious, while others haven’t been reported until now, preventing researchers from understanding how they could impact the strain’s behavior, according to a presentation at the briefing.
“Preliminary evidence suggests an increased risk of reinfection with this variant, as compared to other VOCs,” the WHO said in a statement released Friday.
The designation of a new variant of concern coupled with mounting alarm from health officials sent global markets into a tailspin Friday. Oil prices and travel and leisure stocks took heavy losses on the news.
WHO has said it will take weeks to understand how the variant may affect diagnostics, therapeutics and vaccines.
Photo file Caption: A nurse prepares the Pfizer-BioNTech Covid-19 vaccine