On Jun. 21, 2012, the European Region of the world was certified as polio-free. Certification followed years of intensive effort by Member States, supported by a public–private coalition of WHO, the United Nations Children’s Fund (UNICEF), Rotary International and the U.S. Centers for Disease Control and Prevention (CDC).

The countries demonstrated the value of large, internationally coordinated vaccination campaigns and of special efforts to reach traditionally under-served groups, such as migrants or nomads. In 2010, immunity had dropped to the point where an importation of wild poliovirus type 1 led to a large polio outbreak in Tajikistan and three neighboring countries. This outbreak paralysed 478 people – including many adults – and killed 29.