The anonymous official, speaking to Reuters, said a lot remains unknown about the virus - but some of its 40 mutations indicate the potential for higher transmission rates than other variants.

       Emerging reports suggest many cases of Omicron are mild. On Tuesday, a senior official in Botswana's health ministry said 16 out of the 19 cases of the Omicron variant detected in the country were asymptomatic.

       It could be towards "the end of the month" before we get a clearer picture of how worrying the Omicron variant is, according to Professor Neil Ferguson.

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