A century ago a deadly flu virus swept the planet, uniting the world in a disaster on a par with World War One.Over 50 million people died. Social distancing was put in place but drugs were ineffective, there was no vaccine, and in many places medicine could not cope. The world recovered but was never the same again. What can the last great pandemic teach us about how to combat Covid-19 today? Three world experts join Bridget Kendall: Laura Spinney, science journalist and author of Pale Rider: The Spanish Flu of 1918 and How it Changed the World;. Svenn Erik Mamelund, historical demographer and research professor at Oslo Metropolitan University; Siddharth Chandra, director of the Asian Studies Centre and professor at James Madison College, Michigan State University. (Photo: Japanese school girls wear protective masks to guard against the influenza outbreak. Credit: Bettmann/Getty Images)