Prison inmates constitute a vulnerable population, in which socially excluded, poor and marginalized individuals are overrepresented and infectious diseases are more prevalent than in the general population. The poor health of inmates and recently released inmates is a rarely studied public health problem. The health trajectories of inmates living with the hepatitis C virus is an interesting case study to discuss public health interventions in prison. It is presented here as part of a socio-anthropological study of inmates and healthcare professionals in France. These trajectories shed light on treatment and healthcare experiences, within their economic, social, material and institutional constraints. They are an integral part of the public debate on prison health in France, comprising two prominent positions : the “pathogenic prison” and the “healing prison”. These extreme positions in the broader context of this debate provide a better understanding of the context and obstacles to public health initiatives in prison and suggest ways to make them more effective.