VirSim - a model to support pandemic policy making.

A simulation model called VirSim was developed to aid policy making in Sweden. The model simulates the spread of pandemic influenza, using real population data on a national and regional level. Swedish authorities wanted a model that was both quick to run and to implement as a complement to the existing model MicroSim. The possibility to interactively investigate the effect of varying different assumptions was an important aspect. The VirSim model proved useful for comparing different interventions strategies, and for forecasting the societal burden in terms of hospitalization and workplace absenteeism. This paper points out the usefulness of System Dynamics models in public policy making, as a complement to more detailed and time-consuming models.