Covid-19: What do we know about the Omicron variant?

The Omicron variant "is spreading extraordinarily fast in South Africa" and new travel bans are "doing very little to stop the spread" of the new variant, according to a leading vaccines expert.

Speaking to the BBC's Andrew Marr, Professor Willem Hanekom, the director of the Africa Health Research Institute in South Africa, said the first results on how well vaccines work against Omicron "should be out within a week".

Early data reported by scientists in South Africa - where the variant was first detected - suggests Omicron may evade some immunity to Covid-19, although experts caution that the analysis is not definitive.