Global emergencies such as epidemics present immense governance challenges to national, political and operational decision-makers. Modelling and Simulation has been identified as a crucial force multiplier in the development and implementation of preparedness and response measures for epidemics and pandemics outbreaks. Recent years have witnessed an explosion in modelling and simulation tools for this domain while emerging technologies such as IoT and remote sensing enable data collection as an unprecedented scale. However fragmentation and siloing of these efforts hamper their effectiveness. This paper argues that the complexity and scale of the challenge calls for an integrated “Big Modelling” approach which would bring all the different elements together to enable a holistic view and analysis and outlines a computation framework that can act as a catalyst in this direction.