Building Trust Through Transparency: Reimagining Communication in the Secondary Use of Health Data

Abstract Background As AI-driven health data platforms like IDERHA scale across Europe, secondary use of personal health data raises ethical and public health challenges around trust and transparency. Conventional models of transparency, rooted in compliance or disclosure, often fall short in building sustained trust among diverse populations. This study explores how communication practices influence public perceptions of transparency, particularly under uncertainty and in the aftermath of data misuse. Methods Under Work Package 6 (Task 6.2) of the IDERHA project, we conducted two focus groups with patients, citizens, and data holders across multiple European settings. The qualitative study aimed to understand how transparency is experienced and what communication approaches support or undermine trust. Data were thematically analysed to identify key patterns in transparency-related expectations, frustrations, and proposals for improvement. Results Participants expressed dissatisfaction with current transparency practices, citing vague disclosures, limited feedback loops, and inadequate explanations of future data use. Frustration intensified following incidents like data breaches, where apology and accountability were often missing. Participants emphasized the need for specific, accessible, and culturally sensitive communication. They advocated for transparency as a dynamic and reciprocal process, not a one-time disclosure. Conclusions Findings support a shift from transactional to participatory models of transparency. Trustworthy communication should be iterative, inclusive, and responsive-recognising citizens as partners in data governance. These insights inform the design of communication infrastructures for projects like IDERHA and contribute to policy development within the European Health Data Space (EHDS), aiming to improve legitimacy and acceptance of secondary data use. Key messages • Transparency must be ongoing, inclusive, and responsive to sustain public trust in health data sharing. • Apology and accountability are key components of trustworthy communication after data misuse.