POLICY CONTEXT The cross-border access to health data is fragmented, and makes it particularly difficult to reuse health data collected during healthcare. There is a need to initiate and fund a pilot project on health data exchange in collaboration with national authorities in order to facilitate access to European health data repositories through common rules, instruments and procedures. The use cases of this pilot would demonstrate the potential of cross-country re-use of health data for research, policy-making and regulatory activities by connecting the health data permit authorities and other organisations (e.g. research infrastructures) and highlight the potential benefits and added value of a large-scale infrastructure for the reuse of health data. An improved coordination of national efforts and harmonisation of the digital infrastructure and data quality would promote the collaboration of several stakeholders involved in the health data processing towards the delivery of better healthcare to citizens. It would contribute to the creation of an ecosystem of infrastructures relying on common standards and policies to enable integration of currently fragmented national data systems while at the same time provide space for diversity and specificity for each research, policy-making or regulatory needs. The action supports the development of the EHDS and the re-use of health data for the research, policy-making and regulatory activities. It implements the EU4Health Programme’s general objective of ‘strengthening health systems’ (Article 3, point (d)) through the specific objectives defined in Article 4, point (f) of Regulation (EU) 2021/522. OBJECTIVES, SCOPE AND ACTIVITIES This pilot will design, develop, deploy and run a network of nodes (representing different data brokers, holders and data consumers) federated by central services. This pilot will demonstrate and prove the value of an infrastructure ecosystem for the secondary use of health data and assess the ability to scale towards an EU-wide infrastructure. In particular, it will require to: (a) define and select key use cases that build on health data made available by the pilot partners to demonstrate added value of cross-country re-use of health data for policymaking, regulatory and research activities including, for example, the verification of the safety and efficacy of therapeutics; (b) elicit requirements (business, functional and non-functional) for an IT and data infrastructure to enable Union-wide re-use of health data; (c) design the specifications for the building blocks necessary for an IT infrastructure to enable Union-wide re-use of health data; (d) develop, customise or integrate technology to fulfil the agreed requirements; (e) deploy, in conformity with the design specifications, at partner level (nodes) and at central level (federation services), the components necessary for an IT infrastructure to enable Union-wide re-use of health data; (f) run the selected use cases over the implemented IT infrastructure; (g) assess the performance of the technological building blocks used and their ability to scale towards a Union-wide infrastructure; (h) inform on the development of governance arrangements for efficient cross border reuse of data in the context of a digital infrastructure for the secondary use of health data. EXPECTED RESULTS AND IMPACT The expected results of this action are the following: (a) candidate requirements and specifications for the technological building blocks for an IT and data infrastructure to enable EU-wide re-use of health data; (b) deployment of an IT infrastructure consisting of, at least, 6 nodes and central federation services enabling Union-wide re-use of health data; (c) assessment of the proposed technological building blocks having an impact on the potential to scale for a Union-wide solution; (d) inform on evolutions of the development of governance arrangements for a digital infrastructure for efficient cross border re-use of data. This pilot aims at reducing risks and unknowns regarding a Union-wide large scale deployment of an infrastructure for re-use of health data. It would demonstrate the feasibility and added value of a cross-border infrastructure for secondary use of health data. The experience gained in such project would also provide a better understanding of the limitations and the potential of a common EHDS.