Since the very beginning of the COVID-19 pandemic, with mass media and social media playing a key role, anti-vax protests have received sustained attention. The first comments often pointed at the heterogeneity of the events, whose participants seemed to belong to different milieus, from the far right to exoteric groups that opposed mainstream medicine, suggesting alternative ones. In reality, in their forms and claims, these protests developed as a regressive response to the health crisis. Conspiracist beliefs—from the politicized QAnon and Great Replacement conspiracies widespread on the far right to the Chemic Trails and 5G ones present in an exoteric milieu that promoted alternative health practices—were clearly expressed in the slogans and symbols used by the protestors. In different moments in different countries, the contestation of the anti-COVID-19 measures proceeded with picks and ebbs, following the waves of contagion and the related increase in policy measures to curve them. Increasing especially during the vaccination campaigns, they seemed to subside however quite quickly as the COVID-19 virus started to become endemic, with vaccination reducing its lethality. This volume builds upon social movement studies in the attempt to illuminate the dynamics of these protests in the various steps of their emergency, growth and decline. Referring to most recent developments in social movement studies, it in particular contributes to the analysis of contentious politics in emergency times, characterized by deep disruption in everyday life and rapid structural transformations in the society. In order to understand how specific strains are transformed into actions, it considers the opportunities and challenges for different actors in moments of intense mobilization in which different and contrasting claims are put forward. While these moments are rich in innovation, they built upon existing social movement infrastructures, that contribute to give meaning to dissatisfaction by proposing a shared definition of problems and solutions. Looking at the wave of anti-vax protests through the lenses of social movement studies, the analysis addresses the spread of the protests, their forms, but also their quick decline.