Fragile and conflict-affected states (FCS) often struggle with building their capacity, ending conflict, and creating peaceful options for the future. But strengthening state capacity is limited by the amount and type of resources a state has, the reach and resilience of different infrastructures (e.g., roads, supply lines), limitations on consolidation efforts, and a lack of control over the use of violence. The provision of services, particularly education, clean water, and electricity, has been linked to efforts of states to increase their capacity, but these provisions rarely follow a linear path nor are they always effective. Times of crisis, such as during epidemics, can exacerbate the challenges that link service provision to building legitimacy for states, particularly for societies facing ongoing conflict, but the provision of – certain – services can have a positive effect on state legitimacy. I argue that under certain conditions – through leveraging polycentric governance structures and learning – vaccination campaigns act as a specific type of service provision that allows the state to build legitimacy. This legitimacy-building will then lay the foundation for the state to start increasing both their material capacity and their ability to end conflict. I trace successive outbreaks of Ebola in Équateur Province in the Democratic Republic of the Congo and show that by partnering effectively with international organizations, local leaders, and former rebel leaders, the state was able to learn from previous failed outcomes and increase its legitimacy and convince citizens to get vaccinated and adopt different funeral practices to prevent Ebola from spreading as far or as quickly as in the past. This feedback learning mechanism increased state legitimacy in Équateur Province in a relatively short time frame and has persisted.
