The World Health Organisation (WHO) has said 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 is limited, Reuters reports.

"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 November 29.

It is unclear whether Omicron is inherently more contagious than the globally dominant Delta variant, the WHO said.

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