Last week, a new variant of Covid-19 was detected by scientists in South Africa. Since then, additional cases have been reported beyond southern Africa, including Belgium, Canada, Israel, Australia and the UK. And with the WHO warning that the Omicron variant poses a very high global risk, scientists around the world are scrambling to uncover clues about its transmissibility and how effective the current coronavirus vaccines will be against it. To find out what we do know about Omicron and what it could mean for the coming weeks and months, Madeleine Finlay spoke to the Guardian’s science editor, Ian Sample. This podcast was amended on 30 Nov 2021. An earlier version incorrectly claimed that Covid cases in South Africa had reached around 6,000 per day. Help support our independent journalism at theguardian.com/sciencepod