Disease outbreaks can have substantial health, economic and social costs. The public health imperative during an outbreak is therefore to control the event as quickly as possible in order to minimize morbidity, mortality and other negative impacts. Communication is integral to every public health response. It provides the basis for and precedes actions taken by people who are affected or at risk and the actions of people who are trying to respond. Yet, communication strategies are often designed after outbreak investigations and outside operational decision-making. As a result, the focus of communication has usually been message development and information dissemination. COMBI is a planning framework and implementation method that integrates behavioral and social communication interventions within public health programmes. Consequently, this toolkit represents a fundamental shift in the understanding and application of communication in an outbreak