What is a public health emergency (PHEIC)?

What the International Health Regulations are

The PHEIC is a creature of the International Health Regulations (2005), known as the IHR (2005): a binding international legal agreement involving 196 countries across the globe, including all the Member States of WHO. Its purpose is to prevent, protect against, control and provide a public health response to the international spread of disease in ways that are commensurate with and restricted to public health risks, and which avoid unnecessary interference with international traffic and trade.

The Regulations were revised in 2005 after the SARS outbreak of 2002–2004, and entered into force on 15 June 2007. They are the reason a PHEIC is a legal act, not just a warning: under the IHR (2005), States Parties have a legal duty to respond promptly to a PHEIC. For the system around the Regulations — surveillance, the Global Health Security Agenda, and the WHO Pandemic Agreement — see the guide on what is global health security?.

The four questions countries ask before reporting

When an unusual health event appears, each country assesses it with the decision instrument in Annex 2 of the IHR (2005). It asks four questions:

1. Is the public health impact of the event serious?
2. Is the event unusual or unexpected?
3. Is there a significant risk of international spread?
4. Is there a significant risk of international travel or trade restrictions?

If any two are answered yes, the country must notify WHO — within 24 hours of assessing the public health information. Four diseases skip the decision instrument entirely and are always notifiable: SARS, smallpox, wild-type poliomyelitis, and human influenza caused by a new subtype. A PHEIC itself is not limited to infectious diseases: the Regulations also cover events caused by biological, radionuclear or chemical agents, and events of unknown cause.

Who decides: the Director-General, advised by the Emergency Committee

Internationally, only the WHO Director-General can declare a PHEIC. The Director-General makes the final determination, and issues the Temporary Recommendations, based on advice from the Emergency Committee, information provided by the States Parties, scientific experts, and an assessment of the risk to human health, the risk of international spread, and the risk of interference with international travel.

The Emergency Committee is made up of international experts drawn from the IHR Experts Roster, with at least one member nominated by the State Party in whose territory the event arises. It provides views on three things: whether the event is a PHEIC, the Temporary Recommendations that should follow, and when the PHEIC should end. It advises; it cannot declare. States Parties must report a possible PHEIC to WHO within 24 hours, but they cannot declare one either.

Nationally, the picture is different, and there is no single global answer: who can declare a domestic public health emergency — a head of state, a health minister, a governor — depends on each country’s own law.

What happens after a PHEIC is declared

Once a PHEIC is declared, the Director-General issues Temporary Recommendations: measures that should be taken by the country experiencing the emergency, or by other countries, to prevent or reduce the international spread of disease and avoid unnecessary interference with international trade and travel. States Parties have a legal duty to respond promptly.

Nothing about the response is open-ended. Temporary Recommendations automatically expire three months after they are issued, so the Emergency Committee is reconvened at least every three months to review the epidemiological situation and whether the event continues to be a public health emergency of international concern. A statement of the Committee’s meeting is published on WHO’s website after each meeting.

Ending a PHEIC does not mean the disease is gone. Mpox was declared a PHEIC twice — in 2022 and again in 2024 — and the second declaration ended on 5 September 2025, while the outbreak continued. What followed was not the end of the rules but a change of instrument: the Director-General’s standing recommendations for mpox were extended, and are in effect for all States Parties until 20 August 2027 (WHO, Geneva, 17 August 2026). The previous extension had run to 20 August 2026.

How long can a PHEIC last?

There is no fixed maximum length in the IHR (2005). A PHEIC lasts while the criteria are met — which can be a very long time. The poliovirus PHEIC, declared on 5 May 2014, was still ongoing in 2026, more than twelve years later. What is time-limited is the response: the Temporary Recommendations expire after three months unless the Committee reconvenes and the Director-General reissues them.

PHEIC vs pandemic: not the same thing

The two terms are often used as if they were interchangeable. They are not. A PHEIC is a formal designation, giving a special status for an emergency, tied to international law through the International Health Regulations — the strongest global alert WHO can formally make, with a legal duty on countries to respond quickly (Chatham House, 19 October 2022). “Pandemic”, by contrast, has no agreed definition, no infrastructure around decision-making, no agreed criteria, and no agreement on what countries must do in response. It is a descriptive term.

The COVID-19 sequence shows the gap. WHO declared COVID-19 a PHEIC on 30 January 2020, and called it a pandemic on 11 March 2020 — six weeks later. WHO has formally declared a pandemic only twice in the modern era: H1N1 in 2009 and COVID-19 in 2020. The language is still evolving: the 2024 amendments to the IHR added a “pandemic emergency” label, so the vocabulary around the top of the scale may change again. For what is happening now, read pandemics happening now.

The nine PHEICs since 2009

Nine declarations since 2009, and two still active: poliovirus, and Ebola disease caused by Bundibugyo virus, declared on 17 May 2026. The Bundibugyo outbreak is covered in two guides on this site: the Ebola (Bundibugyo) outbreak guide, which explains the outbreak itself, and Ebola Bundibugyo 2026: outbreak and vaccines, which covers the Tumaini vaccine trial and the conflicting death tolls.

What powers does a declaration unlock?

Internationally, a PHEIC triggers the Director-General’s Temporary Recommendations and the legal duty on States Parties to respond promptly. The Emergency Committee’s remit covers the determination itself, the recommendations, and termination. That is the whole of the international answer.

Nationally, the powers unlocked — quarantine, movement restrictions, requisitioning, emergency spending — depend entirely on each country’s own emergency law. No WHO source gives a universal list, and this guide does not publish one as if it applied everywhere. What a declaration unlocks in any given country is a question for that country’s law, not for the IHR.

Why an outbreak becomes an international issue

An outbreak becomes an international issue, rather than just a domestic health issue, when it meets the PHEIC definition: it is an extraordinary event that carries a public health risk to other States through the international spread of disease, and may require a coordinated international response. That is the threshold the IHR (2005) sets — serious, sudden, unusual or unexpected; carrying implications beyond the affected State’s border; and possibly requiring immediate international action. An outbreak that stays inside one country, however severe, does not meet it.

Frequently asked questions

What does PHEIC stand for?

Public health emergency of international concern — the formal designation under the International Health Regulations (2005) for an extraordinary event that is a public health risk to other States and may require a coordinated international response.

Who can declare a PHEIC?

Only the WHO Director-General. The Emergency Committee of international experts advises on whether an event is a PHEIC, but it cannot declare one. Countries must report a possible PHEIC to WHO within 24 hours, but they cannot declare one either.

How many PHEICs have there been?

Nine since 2009: H1N1 influenza, poliovirus, Ebola in West Africa, Zika, Ebola in Kivu, COVID-19, mpox twice, and Ebola caused by Bundibugyo virus. Two are still active — poliovirus and Ebola (Bundibugyo).

Does a PHEIC mean borders close?

No. The Temporary Recommendations a PHEIC triggers are meant to prevent or reduce the international spread of disease while avoiding unnecessary interference with international traffic and trade.