On 1 January 2020, Sarah Gilbert, Professor of Vaccinology at Oxford University, read an article about four people in China with a strange pneumonia. Within two weeks, she and her team had designed a vaccine against a pathogen that no one had ever seen before. Less than 12 months later, vaccination was rolled out across the world to save millions of lives from Covid-19. In Vaxxers, we hear directly from Professor Gilbert and her colleague Dr Catherine Green as they reveal the inside story of making the Oxford AstraZeneca vaccine and the cutting-edge science and sheer hard work behind it.