parties and WHO. Disease means “an illness or medical condition, irrespective of origin or source, which presents or could present significant harm to humans.” The term event is broadly defined as “a manifestation of disease or an occurrence that creates a potential for disease.” Public health risk refers to “a likelihood of an event that may affect adversely the health of human populations, with an emphasis on one which may spread internationally or may present a serious and direct danger.” A public health emergency of international concern (PHEIC) is defined as “an extraordinary event which is determined to constitute a public health risk to other states through the international spread of disease and to potentially require a coordinated international response.” Consequently, events of potential international concern, which require states parties to notify WHO, can extend beyond communicable diseases and arise from any origin or source.
The IHR (2005) introduce a legal framework to support existing and innovative approaches in the global detection of events and response to public health risks and emergencies. Although the IHR (2005) were built in part on the foundations of their predecessor, the IHR (1969), they are primarily based on the recent experiences of WHO and its member states in national surveillance systems, epidemic intelligence, verification, risk assessment, outbreak alert, and coordination of international response, all of which are part of WHO’s decade-long work to enhance international public health security.
The IHR (2005) have a broad scope, provide for the use of a wide range of information, and emphasize collaborative actions between states parties and WHO in the identification and assessment of events and response to public health risks and emergencies. In WHO’s coordination of the international response to public health emergencies of international concern, maximum measures are replaced by formally recommended and context-specific temporary health measures, tailored to the actual threat faced.
The IHR (2005) are legally binding following their entry into force on June 15, 2007, for all WHO member states that neither rejected them nor filed reservations thereto by the deadline of December 15, 2006. In fact, no member state notified a rejection, and only two member states notified reservations to the director-general of WHO.