Abstract
This study examinesthe complex and often ambiguous conceptualization of consent in European health research, focusing on the relationship between informed consent to participate in research and consent as a legal basis for personal data processing. Differences between these two forms of consent may lead to inconsistent procedures and requirements, thereby generating legal and practical challenges for researchers, ethics committees, data protection authorities, and other oversight bodies. Drawing on two use cases involving observational retrospective studies, the paper compares consent requirements and oversight practices in Belgium, the Czech Republic, Finland, France, Germany, Italy, Poland, and Spain, highlighting persistent fragmentation and uneven institutional coordination across national research governance systems. The paper also distinguishes between ‘monist’ conceptions of consent, which view research and data protection consent as expressions of a single normative concept, and ‘dualist’ conceptions, which treat them as distinct forms of authorization grounded in different ethical and legal rationales. The paper concludes by reflecting on the implications of the upcoming European Health Data Space Regulation, arguing that its approach to secondary data use may further accentuate existing tensions and highlighting the need for greater conceptual clarity and institutional coordination in European health research governance. KEYWORDS: consent, opt-out, research ethics, data protection law, retrospective observational research, ethics committees, data protection authorities, European Health Data Space (EHDS)