Abstract
The advent of smallpox vaccine in France in 1800 inaugurates a new relationship between administration, public health and the definition of medical facts. As Napoleon himself refused to establish compulsory vaccination, a Comité de vaccine was established so as to impose the idea of a riskless vaccine protecting forever from smallpox. This article studies how human experimentation, clinical experience, medical imagery and statistics maintained the idea of a perfect vaccine for six decades, despite the multiplication of cases of post-vaccination smallpox and vaccine contaminations.