The growing success of the epidemic horror films needs explanation. One answer is that the fans of the genre are ready to endure horror in order to see and know what horror the idea of epidemics can inspire them with. The horror epidemic films are variations and revisions on a story which shows characters forced by the epidemic threat to run away and to embrace skepticism. For fugitives, the only way to live with it is to be faithful to themselves. But the epidemic threat is a certainty which offers no other certainty : the skepticism it causes indeed works against self-knowledge. Horror is the emotion one feels when one begins to doubt of oneself and of one’s own faithfulness under the threat of contamination. The horror epidemic films may contaminate the spectators with skepticism but they also may reveal a way to overcome it.