Terveyden ja hyvinvoinnin laitos THL (Finnish Institute for Health and Welfare) is a research and development institute under the Finnish Ministry of Social Affairs and Health. THL is the national competence center and competent authority for eHealth infrastructure, i.e. responsible for the planning, management and monitoring of the electronic processing of client data in health care and social welfare as well as for the management of related information structures and terminologies. THL is also responsible for the statutory infectious diseases surveillance including COVID-19, in charge of the communicable diseases register (CDR), advising the Ministry of Health on the national vaccination programme (NVP) and holds the vaccine register (NVR) in Finland. THL monitors effectiveness and safety of NVP using individual person identifier linkage between NVR and CDR which allows almost real time surveillance. For statutory purposes, THL can also link other data sources to the NVR and CDR data, and for research purposes upon receipt of ethical permissions also via the Findata, which is a one-stop-shop for the secondary use of open data. Classifications and other information structures with over 200 code sets currently published are managed and distributed via the Code Service of THL. THL has participated in a number of related EU projects such as epSOS LSP, EXPAND, PARENT, ASSESS CT. In its capacity as the statutory statistical authority for health and welfare, THL maintains and promotes the use of a strong knowledge base within the field.