Early Warning and Response to Outbreaks and other Public Health Events: A Guide provides practical guidance for strengthening early warning functions within existing public health surveillance systems in WHO’s South-East Asia Region. The document explains how countries can detect, verify, and respond rapidly to outbreaks and other unusual public health events in line with the International Health Regulations (2005). It describes the five key steps of an Early Warning and Response (EWAR) system—information collection, signal detection, event verification, response, and communication—and outlines how to set alert thresholds, identify signals, and ensure timely reporting. The guide also includes recommendations for monitoring and evaluating system performance to improve timeliness, sensitivity, and overall effectiveness in preventing and controlling public health threats.