The International Health Regulations bind 196 countries, and only the WHO Director-General can declare a public health emergency of international concern

Background

The International Health Regulations (2005), or IHR (2005), are a binding international legal agreement involving 196 countries, including all the Member States of WHO.
Their purpose is to prevent, protect against, control and provide a public health response to the international spread of disease, in ways that avoid unnecessary interference with international traffic and trade.
The IHR (2005) define a public health emergency of international concern (PHEIC) as an extraordinary event determined to constitute a public health risk to other States through the international spread of disease and to potentially require a coordinated international response.
An Emergency Committee of international experts gives the WHO Director-General its views on whether an event is a PHEIC, on the Temporary Recommendations to be taken, and on the termination of a PHEIC.
The final determination of a PHEIC and of the Temporary Recommendations is made by the Director-General, not by the Committee.
Temporary Recommendations automatically expire three months after their issuance, so Emergency Committees are reconvened at least every three months.
Members of an Emergency Committee are drawn from the IHR Experts Roster established by the Director-General, and at least one member should be an expert nominated by the State Party in whose territory the event arises.