Omicron poses "very high" global risk but data on severity limited: WHO

The omicron coronavirus variant, reported in more than 60 countries, poses a "very high" global risk, with some evidence that it evades vaccine protection but clinical data on its severity remain limited, the World Health Organisation (WHO) says.

Considerable uncertainties surround omicron, first detected last month in South Africa and Hong Kong, whose mutations may lead to higher transmissibility and more cases of COVID-19 disease, the WHO said in a technical brief issued on Sunday.

"The overall risk related to the new variant of concern omicron remains very high for a number of reasons," it said, reiterating its first assessment of Nov. 29.

"And second, preliminary evidence suggests potential humoral immune escape against infection and high transmission rates, which could lead to further surges with severe consequences," the WHO said, referring to the virus' potential ability to evade immunity provided by antibodies.