CoMix social contact data collected in: - Austria (at) - Belgium (be) - Denmark (dk) - Croatia (hr) - Estonia (ee) - Greece (gr) - Italy (it) - Poland (pl) - Portugal (pt) Format follows the http://www.socialcontactdata.org/ guidelines. Questionnaire available on ECDC website. We gratefully acknowledge the efforts of all teams involved in the implementation of the CoMix study in their country. More specifically: in Austria: the team of Andrea Schmidt at the Austrian National Public Health Institute, in Croatia: the team of Goranka Petrović at the Croatian Institute of Public Health (CIPH), in Denmark: the team of Michael Bang Petersen at Aarhus University, in Estonia: the team of Sigrid Vorobjov at the National Institute for Health Development, in Greece: the team of Elpida Pavi at the University of West Attica (UniWA),in Poland: the team of Magdalena Rosinska at the National Institute of Public Health - National Institute of Hygiene, in Portugal: the team of Baltazar Nunes at the National Health Institute Doutor Ricardo Jorge (INSA), in Italy: the team of Daniela Paolotti at the ISI Foundation. For problems with the dataset, please contact: socialcontactdata@gmail.com Changelog for V2: - Added "country" column in "participant_extra" files to allow easier sub-setting by country. Changelog for V3: - Merged files from different countries in one file.