International Health Regulations


At its annual meeting in June 2007, the Council of State and Territorial Epidemiologists (CSTE) approved a position statement that supports implementation of International Health Regulations (IHR) in the United States (1). CSTE approval followed the adoption of revised IHR in May 2005 by the World Health Assembly (2) that went into effect in the United States on July 18, 2007. This international legal instrument governs the role of the World Health Organization (WHO) and its member countries, including the United States, in identifying, responding to, and sharing information about events that might constitute a Public Health Emergency of International Concern (PHEIC). A PHEIC is an extraordinary event that constitutes a public health risk to other countries through international spread of disease and potentially requires a coordinated international response. All WHO member countries are required to notify WHO of a potential PHEIC. WHO makes the final determination about the existence of a PHEIC.

Healthcare providers in the United States are required to report diseases, conditions, and outbreaks determined to be reportable by local, state, or territorial law or regulation. In addition, all healthcare providers should work with their local, state, or territorial health agencies to identify and report events occurring in their location that might constitute a PHEIC. U.S. state and territorial departments of health report information about a potential PHEIC to the most relevant federal agency responsible for monitoring such an event. In the case of human diseases, the U.S. state or territorial departments of health notify CDC through existing formal and informal reporting mechanisms (1). CDC further analyzes the event by use of the decision algorithm in Annex 2 of the IHR and notifies the U.S. Department of Health and Human Services (DHHS) Secretary’s Operations Center (SOC), as appropriate. The HHS SOC is responsible for reporting a potential PHEIC to WHO.

In the United States, DHHS has the lead role in carrying out IHR, in cooperation with multiple federal departments and agencies. When a potential PHEIC is identified, the United States has 48 hours to assess the risk of the reported event. If authorities determine that a potential PHEIC exists, the United States, as with all WHO member countries, has 24 hours to report the event to WHO. The DHHS SOC is responsible for reporting a potential PHEIC to WHO.

Determining Whether To Report an Event

An IHR decision algorithm (Annex 2 of the IHR) was developed to help countries determine whether an event should be reported. If any two of the following four questions are answered in the affirmative, then a potential PHEIC exists and WHO should be notified:

  • 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 for international travel or trade restrictions?

The revised IHR reflects a conceptual shift from the use of a predefined disease list to a framework of reporting and responding to events on the basis of an assessment of public health criteria, including seriousness, unexpectedness, and international travel and trade implications. A PHEIC is an event that falls within those criteria (further defined in a decision algorithm in Annex 2 of the revised IHR); however, any one of the following four conditions always constitutes a PHEIC and does not require the use of the IHR decision instrument in Annex 2:

  • severe acute respiratory syndrome (SARS),
  • smallpox,
  • poliomyelitis caused by wild-type poliovirus, and
  • human influenza caused by a new subtype.

Examples of events that require the use of the decision instrument include, but are not limited to, cholera, pneumonic plague, yellow fever, West Nile fever, viral hemorrhagic fevers, and meningococcal disease. Other biologic, chemical, or radiologic events that fit the decision algorithm also must be reported to WHO.

Additional Resources

Additional information about IHR is available at,, and

CSTE also approved a position statement that added initial detections of novel influenza A virus infections to the list of national notifiable infectious diseases, beginning in January 2007 to, in part, support the implementation of the revised IHR in the United States to identify human influenza caused by a new subtype (3).

  1. CSTE. Events that may constitute a public health emergency of international concern. Position statement 07-ID-06.
  2. WHO. International Health Regulations, Second ed. Geneva, Switzerland: World Health Organization; 2005.
  3. CSTE. CSTE position statement; 2007. National reporting for initial detections of novel influenza A viruses.