Infectious disease pandemics have plagued us – and other animal species – for as long as we know. These pandemics are of great concern for health, humanitarian, and national security reasons. What is being done to prevent such pandemics from starting, and what can be done to mitigate their effects if they do happen. Pandemics are very difficult to prepare and plan for because they are events that have a low probability of occurring, but the impact could be huge. How much money should we spend preparing for pandemics – or should we spend that money in other critical areas? Can science help us make these decisions?