This book provides a comprehensive guide to the Polio virus Outbreak Response Assessment (OBRA), detailing the strategies and methodologies used to assess and enhance vaccination and surveillance efforts to stop poliovirus transmission. It targets public health professionals and policymakers involved in outbreak management. The text outlines objectives such as increasing immunization coverage, understanding the causes of outbreaks, and strengthening surveillance systems. It emphasizes the importance of timely response, effective planning, and coordination among international health organizations like WHO and UNICEF. The book also addresses the management of vaccine stocks and the criteria for determining the end of an outbreak.