For a vaccine to work, people need to take it. But some are hesitant. On this week's How to Vaccinate the World, Tim Harford looks at why some people have concerns about taking a new coronavirus vaccine - and discussing how health providers, governments and the media should be responding. Tim is joined this week by GP Margaret McCartney, Marianna Spring, BBC Disinformation and Social Media Correspondent, and Professor Heidi Larson, Director of The Vaccine Confidence Project at London School of Hygiene and Tropical Medicine and author of Stuck: How Vaccine Rumours Start.