Emma explains that a PHEIC is a formal designation, giving a special status for an emergency caused by an infectious disease outbreak from the World Health Organization (WHO), tied to international law through the International Health Regulations (IHR).
IHR define what countries are supposed to do to prevent, prepare for, and respond to infectious disease emergencies or other public health events across borders.
A PHEIC is the strongest global alert the WHO can formally make and, when it is declared, countries have a legal duty to respond quickly, whereas with a pandemic there is no infrastructure around the decision-making process, agreed criteria, or agreement of what countries need to do in response.
Although there is not even a universally agreed definition of a pandemic, it can be argued this term may have more impact than a PHEIC as many well-known outbreaks which spread internationally are not declared as a PHEIC.