The World Health Organization (WHO) uses the term "public health emergency of international concern" (PHEIC) to refer to "an extraordinary event" concerning public health.
How does the WHO define a PHEIC?
There are two criteria to define an outbreak as such. Firstly, the outbreak must pose a risk to more than one country.
The second requirement is that an outbreak requires "a coordinated international response."
In the WHO's official definition, they say this means a "situation that is serious, unusual or unexpected."
A panel of experts, called the IHR Emergency Committee, is convened to discuss the situation. IHR stands for International Health Regulations — 196 countries including all WHO member states agreed to its most recent revision in 2005.
Ultimately, after assessing evidence including human-to-human transmission rates, the final decision rests with the WHO Director General, currently Tedros Adhanom Ghebreyesus.
How often does the WHO designate outbreaks as PHEICs?
The WHO has made such a declaration roughly once every two years since the term was coined.
The WHO tends to be cautious in declaring public health emergencies, as it also weighs up the economic risks and the impact on industries like tourism. The regulations specifically seek to "avoid unnecessary interference with international traffic and trade."
The WHO has also faced considerable criticism in the past for being either to quick or too slow to declare a global health emergency.
The procedures to declare a PHEIC were implemented in 2005, as a response to the outbreaks of SARS and H5N1 (bird flu) in the early 2000s.
Six emergencies have been declared since then: the H1N1 virus (better known as a strain of "swine flu") that caused an influenza pandemic (2009), West Africa's Ebola outbreak (2014-2016), polio (2014), the Zika virus (2016), the ongoing Ebola outbreak in the Democratic Republic of Congo (2019), and the current new coronavirus outbreak (starting at the end of 2019).
It took a year after the outbreak of Ebola in the Democratic Republic of Congo for the WHO to declare it a PHEIC.
What does the PHEIC status mean?
A declaration would lead to a boost in public health measures, funding and resources to prevent and reduce international spread.
The measures could include recommendations on trade and travel, including airport screening of passengers — although the WHO generally aims to avoid disruptive trade restrictions.
Under the WHO's current regulations for managing such situations, the emphasis is on containing an outbreak at its source. They also require countries to be transparent with information about the outbreak and be prepared to isolate patients who are infected.