Online misinformation about polio has gone global after the detection of so called vaccine-derived poliovirus in London sewage. BBC health and science correspondent James Gallagher explains what’s really happening. And Claudia Hammond talks to Professor Beate Kampmann from the London School of Hygiene and Tropical Medicine who explains that while vaccine-derived polio virus has been reported in 24 countries since 2021 the vaccination programme has protected millions of people. Plus why looking after your body clock can be good for your health. Professor Russell Foster unpicks how our circadian rhythms can have an impact on the way our bodies deal with the food we eat, the exercise we do and medications we take. Presenter: Claudia Hammond Producer: Erika Wright (Picture: Someone using a mobile phone indoors. Photo credit: Charday Penn/Getty Images.)