Alert & Response Programme

The AHO team provides support for members in establishing and implementing functional integrated early warning and response systems in order to improve early detection and rapid response to epidemic-prone diseases with pandemic potential and other public health emergencies.

The team collaborates with AHO in carrying out:

  • Event surveillance
  • Risk assessment 
  • Information management and dissemination
  • Response

AHO tracks the evolving infectious disease situation, as well as events related to contaminated goods, food safety, or of chemical or radionuclear origins, to alert governments, when needed, as well as to share technical expertise, and mount the kind of response needed to protect populations from the consequences of epidemics, whatever and wherever might be their origin.

For this purpose, permanent communication channels between governments and the AHO have to be established and are routinely tested to ensure access.

The International Health Regulations (2005) or “IHR (2005)” provide a framework for AHO to control international outbreaks and other public health risks and emergencies.  When the IHR (2005) went into force on 15 June 2007, new operational concepts were introduced.

Key operational elements introduced by the IHR (2005) falling under the care of AHO include:

  • The implementation of specific procedures for notification, consultation, and reporting of public health events.
  • The establishment of permanent communication channels, 24 hours a day, 7 days a week, between governments and the AHO Contact Point.
  • Sending verification requests to IHR National Focal Points, regarding reports of public health events occurring within territories.

The IHR (2005) also includes the offer of international collaboration to countries affected or threatened by an emergency. This collaboration includes guidance and technical cooperation, the mobilisation of international experts to provide assistance in the field and provision of the supplies needed to respond to the situation


Event Surveillance

Identifying Events

In addition to directly receiving information from governments, AHO team continuously screens informal or unofficial information sources to detect events or situations that may threaten international public health and for which governments may require assistance.  The team gathers official reports and identifies rumors of suspected public health events from a wide range of sources.


Initial Screening of event information

Information obtained from unofficial or informal event information undergoes an initial screening, referred to as the initial risk assessment.  A risk assessment is not considered complete until the event is verified by the government.


Verifying Information

After the initial detection of an event is made from informal or extraofficial sources AHO verifies the information with the government.  Requests for verification are sent to the government‘s National IHR Focal Point (NFP).


Risk Assessment

Risk assessment is the process of evaluating the probability and consequences of injury or an event arising from exposure to identified risks.

It is an interactive process that is initiated upon the detection of an event and continues until such event is under control. Risk assessment requires an interdisciplinary approach and the participation of technical experts.

Following a risk assessment, the IHR Annex 2 decision instrument for the assessment and notification of events is used by governments to decide whether an acute public heath event requires formal notification to the AHO. The effective use of Annex 2 depends on the national authorities of each country and their respective IHR National Focal Point (NFP) who carry out the risk assessments of public health events occurring within their territories.

Decision instrument for the notification of events

To determine if an event must be notified to the AHO Contact Point, governments must use the following criteria:

  • Is the public health impact of the event serious?
  • Is the event unusual or unexpected?
  • Is there a significant risk of international spread?
  • Is there a significant risk of international travel or trade restrictions?

Any event that meets any two out of the four criteria must be reported.  The notification must be made within 24 hours of the assessment made in accordance with the decision instrument of the IHR (2005) Annex 2.

Following notification, communication must continue with accurate and sufficiently detailed public health information on the notified event, where possible including case definitions, laboratory results, source and type of the risk, number of cases and deaths, conditions affecting the spread of the disease and the health measures employed.

In addition, four conditions (smallpox, poliomyelitis due to wild-type poliovirus, human influenza cased by a new subtype, and severe acute respiratory syndrome (SARS)) must be reported to the AHO as they are inherently considered unusual or unexpected and may have serious public health impact.


Risk assessment is an ongoing process that can support one or more of the following actions at any point in time:

  • Discard — events determined to have no present international risk at the time.
  • Monitor — events that are considered to not presently be of international public health importance may require continuous assessment to ensure that they do not later present an international public health emergency.
  • Assist — provision of technical assistance as may be required by Member States.
  • Disseminate — event information to the international community to prepare for or prevent similar events.
  • Escalate — in extreme and rare circumstances the AHO Director may declare an event to be a Public Health Event of International Concern (PHEIC) based on available public health information.  When an immediate global public health response is required to prevent or control the international spread of disease, the IHR(2005) calls on the AHO Director to determine whether an event constitutes a public health emergency of international concern (PHEIC).  In the process, the Emergency Committee, as provided for in the IHR (2005), shall advise the AHO Director with regards to temporary recommendations on appropriate public health measures and requirements for the emergency.

Information Management & Dissemination

The Alert and Response Operations (ARO) team disseminates information about international public health events through the publication of epidemiological alerts, interactive maps and reports available to the public.


Epidemiological Alerts

Epidemiological Alerts provide information about international public health events confirmed with governments; as well as recommendations issued by AHO related to the event in question


Regional Event Management System

The Alert and Response Operations team uses the AHO developed “Event Management System” to manage information on events in Africa. This system makes it possible to disseminate critical event-related information between international public health professionals, including the AHO and specialized centres.

The following types of information are stored in the system:

  • Epidemiological situation
  • Event verification
  • Laboratory
  • Field operations
  • Tracking and recording outbreak history
  • Critical decisions
  • Important actions carried out by AHO and partners


The IHR (2005) includes the offer of international collaboration to countries affected or threatened by an emergency, which includes guidance and technical cooperation, the mobilization of international experts to provide assistance in the field, and provision of the supplies needed to deal with the situation.