In this article I discuss the definition of "the Antivaccine Movement" using the case of the French controversy over the safety of the 2009 pandemic flu vaccine. I show that the group of main actors who criticized the vaccine's safety is heterogeneous. This heterogeneity can be found in the type of arguments mobilized to question the vaccine's safety and in these actors' likelihood of being involved in any vaccinerelated controversies. I show that only a minority of these actors rejected vaccination in general and mobilized against all vaccination campaigns. Most of these actors only occasionally mobilized against a given vaccine or vaccination campaign and they did so to promote a political or cultural agenda that went beyond the vaccine itself. Using these results, I argue that in order to better understand how vaccinerelated controversies emerge and why some activists devote time and resources to spread vaccinecritical arguments, social scientists should use three distinct concepts to refer to vaccine criticism: The Antivaccine Movement, the Marginally Antivaccine Movements and the Occasionally Vaccine Critical Movements. To do so would enable social scientists and public health experts to better understand the different ways in which vaccination can become politicized and the evolution of this politicization.