Linking existing Early Warning, Alert and Response Systems (EWARS) for Emergencies

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(This was conceptualised in 2014 in a country where there was established EWARS in place)

Background: During a disaster, it is essential to establish disease surveillance system with an early warning mechanism to ensure the early reporting of cases, to monitor disease trends, and to facilitate rapid detection and response to outbreaks. WHO has developed a guideline on establishing early warning systems after the disaster as Early Warning Alert and Response Network (EWARN).[1] It has stressed that it was important not to assume any prior knowledge of EWARN and ensure the document offered practical, operational guidance for implementing EWARN in a step-by-step format, for use at the field level emergency.

At the same time, it also says on the implementation of an EWARS can range from strengthening the existing early warning and response component of a routine surveillance system to implementing a completely new system if nothing appropriate is currently in place. There is some evidence of linking existing system of early warning for the disaster (Disease Early Warning System- DEWS during flooding in Pakistan, the early warning system in Haiti due to earthquake).[2] Several Pacific Island Countries are working to integrate routine disease surveillance with post-disaster risk assessments and early warning surveillance and response systems. The Solomon Islands, in particular, has demonstrated how to assess and respond effectively to disease threats in post-disaster settings.[3]

However, there is still a question of how many countries from the developing world that have functioning early warning system for disease surveillance have linked with disaster management. Those countries, who have demonstrated, as mentioned above, has not linked to routine, and functional early warning system for disaster after the disaster response is over.

The rationale for linking the existing early warning system for emergencies:

  1. Provides an opportunity to link with existing or developing systems. Many countries have either already established or established an early warning system to strengthen surveillance capacities required for IHR (2005) implementation. This will give opportunities to strengthen surveillance capacities to detect, verify, assess, inform and respond to potential threats during emergencies.
  2. Saves resources for implementation and immediately after disasters: the early warning system can instantly support for emergencies.
  3. During a disaster, the existing system may disrupt, and most of the system has developed a continuity plan as part of a contingency plan for disasters/emergencies. (WHO Guideline also mentions that the existing system may disrupt during emergencies due to emergencies and the early warning system’s establishment is required).
  4. This can further advocate the government to develop continuity planning for surveillance for disaster and as well as for other health services.
  5. Not all disasters will disrupt completely existing surveillance system.

How to link the existing early warning system:

  • Use the existing early warning system of the surveillance system for early warning during emergencies.
  • Incorporate topic on surveillance for disaster on routine training of surveillance and EWARS of clinicians and health care workers on followings:
    • Recognizing priority diseases (Case definitions);
    • Reporting cases and mechanism to the existing system during disaster/emergencies
    • Application of the alert threshold
      • Sound an early warning and launching of an  investigation
      • Check epidemic preparedness and response (vaccination)
      • Prioritize the interventions
    • Use of epidemic threshold to confirm the emergence of an outbreak and to put control measures accordingly.
    • Laboratory Diagnosis for emergencies
    • In the absence of emergencies, simulate them with two scenarios.
      • First: without disruption of existing EWARS and
      • Second: with disruption of existing EWARS
    • Develop a continuity plan as part of contingency plan of disaster (– use WHO guideline to set up and train surveillance team on this guideline in advance)
      • Selection of sites
      • A mechanism for relaying data or information
      • Response to alerts
      • Analysis and Feedback
    • Outbreak preparedness
    • Disease Control Initiatives

Step by Step Process of incorporating EWARS for Emergencies: 

  1. Initiate discussion with emergency response team and Surveillance Team if the teams are different.
  2. Establish a working group.
  3. Develop a training curriculum for EWARS training covering surveillance for disaster
  4. Run the training in some of the EWARS regions/districts as a pilot and simulate with two scenarios
    1. First: without disruption of existing EWARS and
    2. Second: with disruption of existing EWARS.


[1] World Health Organization. Outbreak surveillance and response in humanitarian emergencies: WHO guidelines for EWARN implementation. Geneva, 2012

[2] Ministry of Health, Pakistan.  Outbreak Surveillance and Response Disease Early Warning System. Flooding Response in Pakistan. Operational Guidance. Pakistan. 2010

[3] Tenth Pacific Health Ministers Meeting. Outbreak surveillance and response priorities for mitigating the health impact of the disaster. WPRO. Samoa, 2013: Agenda Item 9; PIC10/9

Note: EWARS is an adjunct, not a substitute for the national disease surveillance system. Once the acute emergency phase is over, it should be re-integrated into the national surveillance system.