The global Covid-19 pandemic has put a fierce spotlight on the relationship between scientists and policy makers. Leaders across the world have responded to the science with everything from respect to scepticism. Foremost amongst the sceptics, president Jair Bolsonaro of Brazil, one of the countries hit hardest by the virus. Stephen Sackur speaks to the Brazilian microbiologist Natalia Pasternak who has launched a crusade against her President in the name of science. But is she winning the argument?

(Photo: Microbiologist Natalia Pasternak)