On Wednesday, 194,747 daily confirmed Covid cases were reported for the whole of the UK. But this doesn’t include all the people who have caught the virus for the second, or even third time. In fact, official figures for England, Scotland and Northern Ireland don’t include those who have had Covid before, despite warnings from scientists that up to 15% of Omicron cases could be reinfections. Madeleine Finlay speaks to the Guardian’s science editor Ian Sample about why reinfections are so high for Omicron, what these cases could tell us, and how it could affect public health measures in the future. Help support our independent journalism at theguardian.com/sciencepod