WHO yet to see any reports of Omicron Covid-19 deaths
The WHO said it was collecting evidence about the variant of concern (VOC), as countries around the world scramble to stop it from spreading.
But despite a growing number of countries registering infections with the new variant, no deaths have yet been reported to the UN health agency.
"I have not seen reports of Omicron-related deaths yet," WHO spokesman Christian Lindmeier told reporters in Geneva.
"We're collecting all the evidence and we will find much more evidence as we go along.
"The more countries... keep testing people, and looking specifically into the Omicron variant, we will also find more cases, more information, and, hopefully not, but also possibly deaths."
While Omicron has rattled the world, Lindmeier also urged people to be mindful of the Delta variant, which accounts for 99.8 percent of sequences uploaded to the GISAID global science initiative with specimens collected in the last 60 days.
"Omicron may be on the rise, and we may come to a point where it takes over to be the dominant variant, but at this point, the very dominant variant remains Delta," he stressed.
Lindmeier added: "The restrictions that were put into place in many countries just two weeks ago - economical closures again, lockdowns in some areas, closures of Christmas markets in parts of Europe - this was done before Omicron because of a rise of Delta cases. Let's not lose sight of this."
The spokesman urged people to use proven measures protect themselves against Delta - and thereby against Omicron.
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However, prices dropped by two percent as oil producers decided to go ahead with a planned increase in production despite global Covid-19 concerns. https://t.co/zAO9O9kTlQ
The WHO has said it will take several weeks to get a full picture of the transmissibility and disease severity of Omicron, and to assess how vaccines, tests and treatments hold up against the new variant.
As Omicron spreads, pieces of information are emerging from various countries.
"What we need to do is we need to take all these observations, assessments and tests and get this information together and then have the experts look at it, carefully weigh it and come up with the assessment. That will still take some time," said Lindmeier.
"Preliminary data show that there is higher transmissibility. But that's basically all we have so far."