Professor Jonathan Van-Tam explores the inner workings of vaccines to reveal how these medical marvels can help win the war on viruses and potentially fight diseases such as cancer. Joined by vaccine scientist Professor Teresa Lambe and microbiologist Professor Sharon Peacock, the team peel away the scabs of smallpox and inject the puss of a milkmaid to uncover the key milestones that led to vaccines over 200 years ago. Science has not stopped since. The Covid-19 vaccines are a triumph, but can the audience take them a step further? Can they use a vaccine to blow up cancer cells on the lecture theatre floor?