This article analyzes the application of e demic response models during the Covid-19 epidemic in Guinea and investigates the often-visible discrepancies between these models and the actual practices of care and epidemic management observed on the ground. In the first part, it analyzes how protective measures confront and collide with the ways health care workers actually operate in health centers. It aims to move away from the traditional understanding of Guinean – and more broadly African – health systems as “dysfunctional” (Jaffré & Olivier de Sardan 2003); and from the interpretation of non-compliance with protective measures by health workers and the general population as “resistance” or “reluctance” (Somparé 2020). To this end, it proposes, in the second part, to adopt an ontological approach in order to examine the translation, adaptation and appropriation processes at work in the application of management models by caregivers and the general populace. In the third part, it examines how patients manage epidemic risk within the TC-epi by mobilizing tactics and various ontological repertoires that enable them to negotiate with an invisible virus. The challenge is to mobilize an ontological approach to rethink theories from Africanist anthropology and propose new axes of analysis for African contexts, in particular regarding Covid-19 in Guinea.