Logo of the World Health Organization, the authority that declares PHEICs

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", 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".[1] Under the 2005 International Health Regulations (IHR), states have a legal duty to respond promptly to a PHEIC.[2][3] The declaration is publicized by an IHR Emergency Committee (EC) of international experts,[4] which was developed following the SARS outbreak in 2002–03.[5]

Since 2009, there have been six PHEIC declarations:[6][7] 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,[8] the 2018–20 Kivu Ebola epidemic,[9] and the ongoing COVID-19 pandemic.[10] The recommendations are temporary and require reviews every three months.[1]

SARS, smallpox, wild type poliomyelitis, and any new subtype of human influenza are automatically PHEICs and thus do not require an IHR decision to declare them as such.[11] A PHEIC is not confined to infectious diseases, and may cover an emergency caused by exposure to a chemical agent or radioactive material.[12] In any case within its ambit, it is a "call to action" and "last resort" measure.[13]