ECDC coordinates the surveillance of communicable diseases across Europe. A number of European regulations provide the framework for this activity, including Decisions 2119/98 and 2000/96.

European surveillance is conducted through networks of disease-specific and national surveillance contact points who report data to ECDC on a regular basis. Surveillance in Member States is performed using a variety of data sources and processes that may include population-based systems in which reporting is processed by clinicians (for example, for measles) and/or laboratories (salmonellosis), as well as sentinel surveillance systems, in which only a proportion of practitioners or microbiologists report cases for diseases such as influenza.

EU/EEA Member States report data on an agreed list of 52 communicable diseases and special health issues. Member States use standard case definitions, which help to improve comparability of data across Europe. These case definitions are reviewed by experts from all the Member States and updated regularly as required. The data is uploaded to The European Surveillance System (TESSy), a purpose-built flexible system that allows the collection, validation, cleaning, analysis and dissemination of data. Through this online tool, Member States not only provide their own surveillance data but they also have access to similar data from across Europe. Most data collections are annual, distributed over the year, but data on some diseases are collected more frequently. For example, influenza data is reported weekly to produce the Weekly Influenza Surveillance Overview (WISO), while travel-associated Legionnaires’ disease and diphtheria should be reported within 48 hours after notification to the national level.

A key role of ECDC is to analyse and interpret the data from Member States. This is done both through specific reports on the various communicable diseases and through a number of standardised tables and charts that are available directly from the TESSy website. An overview of all the basic data is also collated in ECDC’s Annual Epidemiological Report on Communicable Diseases in Europe. Researchers may also request raw data from ECDC for further analysis and this is provided under certain conditions and restrictions in agreement with the Member States.