In this episode, we explore how graph analysis can be used to control the spread of contagious diseases. We discuss the difference between the aesthetic of pure math vs. applied statistics when it comes to making sense of graphs, and how this can be applied to identifying people with a high centrality in social networks. We also talk about the Klout score, and how it can be used to prioritize who to quarantine or vaccinate first. Finally, we explore the network properties that made the plague spread so slowly in the Middle Ages, and how this can be applied to other planets with similar conditions.