Freetown is confronted with health-related risks that are compounded by rapid unplanned urbanisation and weak capacities of local government institutions. Addressing such community health risks implies a shared responsibility between government and non-state actors. In low-income communities, the role of Community-Based Organisations (CBOs) in combatting health disasters is well-recognized. Yet, empirical evidence about how CBOs have drawn on their networks and coordinated community-level strategies in responding to the Covid-19 pandemic is scant. Based on a qualitative study in two informal settlements in Freetown, this paper draws on actor-network theory to understand how CBOs problematize Covid-19 as a health risk, interact with other actors and the tensions that arise within these actor networks. The study findings show that community vulnerabilities and past experiences with health disasters such as Ebola informed CBOs' perception of Covid-19 as communal emergency. In response, CBOs coordinated sensitization and mobilization programs by relying on a network of internal and external actors to support Covid-19 risk reduction strategies. Nonetheless, misunderstandings among actors caused tensions in the actor- network. The study suggests that creating new channels for knowledge exchange and building on CBO capacity can help strengthen actor networks in communities and combat current and future health disasters.