The dissemination of misinformation in digital environments constitutes one of the major contemporary challenges for public health and Information Science. This article investigates how vaccine-hesitant subjects construct trust in information sources about vaccines, analyzing informational practices across institutional, digital, and relational contexts. The study was based on semi-structured interviews with participants residing in the United States. Data analysis followed Bardin’s (1977) Content Analysis technique, allowing for the identification of categories related to cognitive authority, the influence of emotions, source triangulation, and the contradiction between declared trust and practice. The results show that trust is socially constructed and modulated by cognitive, affective, and algorithmic factors within an informational regime shaped by the logic of post-truth. The study concludes that strategies to address misinformation require not only clear scientific communication, but also recognition of the role of cognitive biases, social dynamics of validation, and digital structures of visibility.