Trust, Uncertainty, and Governance in Health Data Sharing: Findings from the IDERHA Project

Abstract Background The IDERHA project develops a European-scale data infrastructure to integrate electronic health records, imaging, and patient-generated data for secondary use in research and personalised care. While offering transformative potential, this raises significant public health questions around trust, especially across citizens, borders and institutions. Current frameworks relying on consent and anonymisation may fall short in addressing public concerns. This study investigates how trust in health data sharing is built, maintained, and broken down, under conditions of uncertainty, and asks what governance mechanisms can foster resilient, inclusive, and trustworthy data reuse. Methods We conducted two qualitative studies involving focus groups with patients, citizens, data users, and data holders across diverse European contexts. Discussions explored experiences and expectations around secondary data use, focusing on the relational, emotional, and structural aspects of trust. Workshop data were thematically analysed to identify trust drivers and conditions contributing to trust-breakdowns. Results Participants expressed concern about data misuse, future re-identification risks, and opaque reuse contexts,particularly among marginalised groups. Trust-breakdowns were often catalysed by minor issues such as vague communication or lack of institutional responsiveness. Participants called for anticipatory forms of governance, culturally inclusive communication, and co-designed safeguards. Mistrust was not seen as irrational, but as a legitimate response to uncertainty and past institutional failures. Conclusions Trust in health data reuse cannot rely solely on technical measures. Public health governance must adopt proactive, iterative frameworks that recognise mistrust as a diagnostic tool. Our results inform the evolving European Health Data Space (EHDS) and support the development of inclusive policies and ethical infrastructures for trustworthy health data sharing. Key messages • Trust in health data sharing requires proactive, inclusive governance beyond consent and anonymisation. • Mistrust offers critical insights into ethical blind spots and should guide policy design.