More than a billion doses of covid-19 vaccine have been made. Now comes the hard part: ensuring every country in the world has access to them. Can distribution be made more equitable?    Alok Jha and Natasha Loder are joined by Edward Carr, The Economist’s deputy editor, and Sondre Solstad, senior data journalist.   With Seth Berkley of GAVI, the Vaccine Alliance, and John Nkengasong, director of the Africa Centres for Disease Control and Prevention.   For full access to The Economist’s print, digital and audio editions subscribe at economist.com/thejabpod. Sign up for our new weekly science and data newsletters at economist.com/simplyscience and economist.com/offthecharts    See acast.com/privacy for privacy and opt-out information.