The COVID-19 pandemic has given rise to extensive media coverage characterized, especially in the first few months, by high uncertainty due to the low level of scientific knowledge on the topic. The uncertainty has made it difficult for the press to fulfill their mediation function, that is to say their role in conveying expert information to the public. The present study focuses on the representations of expert knowledge in the press via quotes and the sources they are related to from a contrastive point of view, comparing media representations of the pandemic in Le Monde and in the New York Times. Since quotes increase the legitimacy of news discourse, it is argued that the role granted to experts’ words in the press is an indicator of the journalists’ ethos, which is a particularly sensitive issue in a time of crisis. The study concludes that the way in which journalists build their ethos through text depends on the culture-specific features of their professional specialized domain.