EWAR stands for Early Warning, Alert and Response. EWAR is a system that provides an early warning of acute public health events and then connects this function to an immediate public health response. It is one of the most immediate and important functions of a surveillance system.

• Early warning – the rapid detection of signals that may indicate potential acute public health events. Sources of early warning data may include notifications from health facilities, community members and other entities, which feed into IBS and EBS systems.
• Alert management – the systematic process of managing all incoming information, from signal verification to risk assessment and characterization, in order to decide if a response is required to mitigate the public health risk. For efficiency, all signals should preferably be channelled into a common system so that they can be investigated and managed systematically.
• Response – public health actions triggered by the detection of an alert

1.2 What is the role of EWAR in emergencies?

Emergencies also produce many risk factors that promote the emergence,transmission and outbreaks of communicable diseases, such as: food insecurity and progressive loss of livelihoods; disruption or breakdown of preventative or curative health and other essential services (e.g., access to safe water, sanitation); mass displacement of people into regimented or camp-like settlements or neighbouring 3Prior to EWAR implementation 1. Introduction to EWAR host communities, increasing the risk of overcrowding; sudden loss of livelihoods; and/or rapid environmental change due to a natural disaster (14–16). At the same time, national surveillance systems may be underperforming, disrupted or nonexistent during emergencies, which may adversely impact and delay the detection of and response to outbreaks (17, 18).

These factors can lead to excess morbidity and mortality due to outbreaks, or result in large-scale increases in disease transmission among emergency-affected populations. One of the most urgent priorities in an emergency is, therefore, to establish a functioning EWAR to rapidly detect and respond to events that may lead to outbreaks and other public health emergencies.