During the H1N1 influenza pandemic 2009–2010 in Sweden, a mass-vaccination intervention was enacted as a precautionary measure. Half a year later, medical authorities reported an increased incidence of the life-long neurological disease narcolepsy, later firmly established as a side effect of the pandemic vaccine. Using interview material together with archived protocols, this article presents an analysis of two communities, the National Pandemic Group and the Narcolepsy Association. The aim is to discuss their respective ways of arguing for solidarity, herd immunity, social justice and claim for culpability of the state. Both communities face dilemmas, doubts and double-bind situations, but also perform politics and ethics for the future in mobilizing notions of solidarity and responsibility in their different narratives.