Humanitarian emergencies increase the risk of transmission of infectious diseases and other health conditions such as severe malnutrition. An effective disease surveillance system is essential to detecting disease outbreaks quickly before they spread, cost lives and become difficult to control. WHO’s Early Warning, Alert and Response System (EWARS) is designed to improve disease outbreak detection in emergency settings, such as in countries in conflict or following a natural disaster. It is a simple and cost-effective way to rapidly set up a disease surveillance system.