The notion of transparency regularly comes up in discussions about the secondary uses of health data. Few studies, however, examine the impact of the presence or absence of transparency on members of the public. This literature review responds to this gap in the scientific literature. It is the result of a secondary analysis of 124 texts from an exploratory review on transparency, following the PRISMAS-ScR guidelines. The results help to identify negative or positive impacts and associate these with certain communication (...) components relating to secondary uses of health data. They also make it possible to identify the components associated with communication deemed transparent or opaque by stakeholders. Transparency, and more specifically continuity of communication, is strongly associated with increased trust and social acceptability, whereas members of the public generally perceive a lack of transparency negatively. This literature review also deepens our understanding of the potential negative impacts of transparent communication. (shrink)