States have a legal duty to respond promptly to a PHEIC. Definition PHEIC is defined as: 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. This definition designates a public health crisis of potentially global reach and implies a situation that is "serious, sudden, unusual, or unexpected", which may necessitate immediate international action. It can be seen as an "alarm system", a "call to action" and "last resort" measure. Potential concern reporting WHO Member States have 24 hours within which to report potential PHEIC events to the WHO. It does not have to be a member state that reports a potential outbreak, hence reports to the WHO may also be received informally, by non-governmental sources. Under the IHR (2005), ways to detect, evaluate, notify, and report events were ascertained by all countries in order to avoid PHEICs. The response to public health risks also was decided. The IHR decision algorithm assists WHO Member States in deciding whether a potential PHEIC exists and whether the WHO should be notified. The WHO should be notified if any two of the four following questions are affirmed: Is the public health impact of the event serious? Is the event unusual or unexpected? Is there a significant risk for international spread? Is there a significant risk for international travel or trade restrictions? The PHEIC criteria include a list of diseases that are always notifiable. SARS, smallpox, wild type poliomyelitis, and any new subtype of human influenza are always a PHEIC and do not require an IHR decision to declare them as such. Large scale health emergencies that attract public attention do not necessarily fulfill the criteria to be a PHEIC. ECs were not convened for the cholera outbreak in Haiti, chemical weapons use in Syria, or the Fukushima nuclear disaster in Japan, for example. Further assessment is required for diseases that are prone to becoming pandemics, including, but not limited to cholera, pneumonic plague, yellow fever, and viral hemorrhagic fevers. A declaration of a PHEIC may appear as an economic burden to the state facing the epidemic. Incentives to declare an epidemic are lacking and the PHEIC may be seen as placing limitations on trade in countries that already are struggling. Emergency Committee In order to declare a PHEIC, the WHO Director-General is required to