European Centre for Disease Prevention and Control, European Centre for Disease Prevention and Control, European Centre for Disease Prevention and Control, European Centre for Disease Prevention and Control, Superintendence of Public Health - Infectious Disease Prevention and Control Unit, Superintendence of Public Health, Superintendence of Public Health - Infectious Disease Prevention and Control Unit, National Institute of Public Health (Prague) - Department of Biostatistics, National Institute of Public Health (Prague) - Department of Biostatistics, National Institute of Public Health (Czech Republic) - Department of Infectious Diseases Epidemiology, National Institute of Public Health (Prague) - Department of Biostatistics, Norwegian Institute of Public Health - Division of Infection Control and Environmental Health, Norwegian Institute of Public Health - Division of Infection Control and Environmental Health, Norwegian Institute of Public HealthNorwegian Institute of Public Health - Division of Infection Control and Environmental Health, Norwegian Institute of Public Health - Division of Infection Control and Environmental Health, Health Directorate, Luxembourg, Health Directorate, Luxembourg, Health Directorate, Luxembourg, Health Protection Surveillance Centre (HPSC), Health Protection Surveillance Centre (HPSC), Health Protection Surveillance Centre (HPSC), Health Protection Surveillance Centre (HPSC), World Health Organization (WHO) - World Health Organization Regional Office for Europe, World Health Organization (WHO) - World Health Organization Regional Office for Europe and European Centre for Disease Prevention and Control

Harvard University - Global Health Program, Epiconcept, Government of Albania - Institute of Public Health, Government of Albania - Institute of Public Health, Southeast European Center for Surveillance and Control of Infectious Disease, Government of Albania - Institute of Public Health, Government of Albania - Institute of Public Health, Government of Albania - Institute of Public Health, Government of Albania - Institute of Public Health, Harvard University - Global Health Program, Harvard University - Global Health Program, World Health Organization (WHO) - World Health Organization Regional Office for Europe, World Health Organization (WHO) - World Health Organization Regional Office for Europe, World Health Organization (WHO) - World Health Organization Regional Office for Europe, Charité - Universitätsmedizin Berlin - Institute of Virology, World Health Organization (WHO) - World Health Organization Regional Office for Europe, World Health Organization (WHO) - World Health Organization Regional Office for Europe, Epiconcept, Government of the United States of America - Influenza Division, World Health Organization (WHO) - World Health Organization Regional Office for Europe and Government of Albania - Institute of Public Health