This week's panel of guests include President Biden’s Chief Medical Adviser, the long-serving director of the Infectious Disease Institute at the US National Institutes of Health, and a doctor who has been played on screen by Brad Pitt. All three of them are, of course, Dr Anthony Fauci. In this episode of How To Vaccinate The World Tim Harford talks with the world famous immunologist about the effectiveness and the roll out of vaccines in the US and around the world, what it’s been like to share a stage with Donald Trump in the depths of a pandemic, and answers questions from some of our loyal listeners. Producers: Sandra Kanthal and Josephine Casserly Listeners questions can be sent to vaccine@bbc.co.uk