WHO names new COVID variant omicron

Preliminary evidence suggested there is an increased risk of reinfection and there had been a "detrimental change in COVID-19 epidemiology," it said in a statement after a closed meeting of independent experts who reviewed the data.

"Today we are announcing B.1.1.529 is a variant of concern named omicron," said WHO technical lead for COVID-19, Maria Van Kerkhove.

Infections in South Africa had risen steeply in recent weeks, coinciding with detection of the variant now designated as omicron, WHO said.

Omicron is the fifth variant to carry such a designation.

"Omicron B.1.1.529 is named as a variant of concern because it has some concerning properties. This variant has a large number of mutations, and some of these mutations have some worrying characteristics," said Van Kerkhove.

Current PCR tests continue to successfully detect the variant, it said.

Earlier, the WHO cautioned countries against hastily imposing travel restrictions linked to the variant of COVID-19, saying they should take a "risk-based and scientific approach."

Global authorities reacted with alarm to the new variant detected in South Africa, with the EU and Britain among those tightening border controls as scientists sought to find out if the mutation was vaccine-resistant.

It would take several weeks to determine the variant's transmissibility and the effectiveness of vaccines and therapeutics against it, he said, noting that 100 sequences of the variant have been reported so far.