In today’s interconnected global society, new diseases can travel through populations at unprecedented rates. Retracing the route that these viruses take through the complex web of human interactions, back to the original host could help us to predict upcoming viral outbreaks, and streamline public health interventions to prevent pandemics in the future. We spoke with David Quammen, author of Spillover, to hear his take on how we can prevent a replication of Covid-19 in the future