More than a billion vaccines have been administered. But the contrast between Israel, largely free of covid-19, and India, struggling with a catastrophic second wave, is stark. What explains the discrepancy?     Devi Sridhar, Founding Director of the Global Health Governance Programme, tells us what to expect as the next billion vaccines roll out.  Alok Jha and Natasha Loder are joined by Slavea Chankova, The Economist’s health-care correspondent, and technology correspondent Hal Hodson. Anshel Pfeffer reports from Israel. 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.