The article discusses mechanisms of social immunisation in the context of the so-called Polish March 1968. Whereas immunising strategies are a normal part of sociality, I argue that around 1968 a growing anxiety about the mechanisms of being-in-common led to an autoimmunitarian dissociation of the Polish society that I will conceptualise as an atmosphere of minusivity. Strategies to counter exclusions and discriminations were trapped in this immunitarian paradigm as well. A crisis of communication arose from the dissonance between the reality created by official language around March 1968, and the reality experienced by many people, as this latter reality was silenced and repressed. Mistrust in language resulted in an immunitarian retreat from affective communication that was replaced by impersonal communicative scripts. This communicative crisis widely prevented the March experiences to condense in cultural production of the time; nonetheless, I will try to retrace some of the immunitarian and counter-immunitarian strategies in literature, film, and retrospective accounts.