During the 2009 H1N1 influenza pandemic nearly every decision associated with new vaccine development and dissemination occurred from the Spring of 2009, when the novel virus first emerged, to the Fall of 2009, when the new vaccines started reaching the thighs, arms and noses of vaccinees. In many ways, 2009 served as a crash course on how mathematical and computational modeling can assist all aspects of vaccine decision-making. Modeling influenced pandemic vaccine decision-making, but not to its fullest potential. The 2009 H1N1 pandemic demonstrated that modeling can help answer questions about new vaccine development, distribution, and administration such as (1) is a vaccine needed, (2) what characteristics should the vaccine have, (3) how should the vaccine be distributed, (4) who should receive the vaccine and in what order and (5) when should vaccination be discontinued? There is no need to wait for another pandemic to enhance the role of modeling, as new vaccine candidates for a variety of infectious diseases are emerging every year. Greater communication between decision makers and modelers can expand the use of modeling in vaccine decision-making to the benefit of all vaccine stakeholders and health around the globe.