It’s almost exactly two years since a cluster of cases of a mysterious pneumonia-like illness were detected in the Chinese province of Wuhan. They were soon identified as coronavirus infections. 24 months later, a new variant, Omicron, has been identified in more than 77 countries. The UK has joined other European countries in re-introducing preventative measures, and amid dire warnings about the pressure on health systems, booster programmes are being accelerated for the luckier nations. In South Africa, where Omicron was first detected, new data suggests it may be milder than previous variants. Simon McGregor-Wood has the latest.