‘We need to be careful about telling people they are immune when they might not be’ – Prof Sarah Walker on Covid-19 study

To ease the lockdown we need a much better understanding of who has had Covid-19, especially if they were not showing any symptoms, who might get it and how badly.

Enter a major new study run by the Department of Health and the Office of National Statistics involving at first 20,000 households. Joining me now is Sarah Walker, who is chief investigator for the study and professor of medical statistics and epidemiology at the University of Oxford.