Based on recent accounts of the sociology of expertise, we analyse the public contestation and expansion of expertise in the context of COVID-19. During the epidemic, the expertise of the Finnish Institute for Health and Welfare (THL), became increasingly contested. By exploring Twitter discussions concerning the actions of THL during the first months of the epidemic from January to mid-June 2020, we analyse the main motivations and arguments in this public contestation as well as the alternative forms of expertise proposed by the critics. We focus particularly on two forms of criticism arguing for what we call networked expertise: liberal crowdsourcing supporters and data-solutionists presenting alternative epidemiological models.