Over the past two years, countries around the world have shut down their societies in last-ditch efforts to contain the pandemic. Some, like China, have enforced strict lockdowns as part of a zero Covid strategy. Others have ordered people to stay at home to flatten the curve of infections and buy precious time. But since they first began, what have we learned about how well lockdowns work? Ian Sample speaks to epidemiologist Prof Adam Kucharski about the effectiveness of different approaches, and the lessons we should take forward.. Help support our independent journalism at theguardian.com/sciencepod