1. Istituto Superiore di Sanità, Laboratorio epidemiologia e biostatistica , Roma, Italia
2. Centers for Disease Control and Prevention, National Immunization Program, Atlanta, USA
3. Instituti e Shendetit Public, Tirana, Albania
4. European Programme for Intervention Epidemiology Training, Brussels, Belgium
5. World Health Organization, Expanded Program on Immunization, Geneva, Switzerland
6. World Health Organization (WHO), Regional Office for Europe, Copenhagen, Denmark