The radical aesthetic of the historical avant-garde movements has often been explained as a reaction to the catastrophic experience of the First World War and a denouncement of the bourgeoisie's responsibility for its horrors. This article explores a blind spot in these familiar interpretations of the international avant-garde. Not only the violence of the World War but also the experience of a worldwide deadly pandemic, the Spanish flu, have moulded the literary and artistic production of the 1920s. In this paper, Susanne Klengel explores this hypothesis through the example of Mário de Andrade's famous book of poetry Pauliceia desvairada (1922), which she reinterpretes in the light of historical studies on the Spanish flu in São Paulo. An in-depth examination of all parts of this important early opus of the Brazilian Modernism shows that Mário de Andrade's poetic images of urban coexistence simultaneously aim at a radical renewal of language and at a melancholic coming to terms with a traumatic pandemic past.