Stock markets have rocketed on hopes of a Covid-19 vaccine breakthrough. The BBC's Business Editor Simon Jack explains who the winners and losers have been on the markets so far, and what this could mean for future stimulus packages and inflation. The drugmakers responsible for the vaccine claim it can prevent more than 90% of people from getting Covid-19. We'll hear from Mikael Dolsten, Global Research Chief for one of the drugmakers Pfizer. And epidemiologist Peter Horby of the University of Oxford expresses guarded optimism for the world opening up again.Produced by Frey Lindsay.(Image credit: Getty Images.)