A Public Health Emergency of International Concern (PHEIC) is a formal declaration by the World Health Organization (WHO) of "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".
[It's] formulated when a situation arises that is "serious, sudden, unusual, or unexpected", which "carries implications for public health beyond the affected state's national border" and "may require immediate international action". Under the 2005 International Health Regulations (IHR), states have a legal duty to respond promptly to a PHEIC.
The declaration is publicized by an IHR Emergency Committee (EC) of international experts, which was developed following the 2002–2004 SARS outbreak. Since 2009, there have been six PHEIC declarations:
the 2009 H1N1 (or swine flu) pandemic
the 2014 polio declaration
the 2014 outbreak of Ebola in Western Africa
the 2015–16 Zika virus epidemic
the 2018–20 Kivu Ebola epidemic
the ongoing COVID-19 pandemic.
The recommendations are temporary and require reviews every three months.
Automatically, SARS, smallpox, wild type poliomyelitis, and any new subtype of human influenza are considered as PHEICs and thus do not require an IHR decision to declare them as such. A PHEIC is not confined to infectious diseases, and may cover an emergency caused by exposure to a chemical agent or radioactive material. It can be seen as an "alarm system", a "call to action" and "last resort" measure.
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