WHO applies an all-hazards approach to public health events that require an immediate response and are potentially caused by more than one hazard — including biological, chemical and radio nuclear hazards, whether naturally occurring or as a result of an accident or deliberate release — and natural disasters such as fires, floods, other extreme weather events, volcanic eruptions, earthquakes and tsunamis.
This approach has been driven by the International Health Regulations (IHR), which were revised in 2005 to reflect growth in international travel and trade, emergence or re-emergence of international disease risks, and threats posed by chemicals, toxins and radiation.
The IHR requires all States Parties to the Regulations to develop a set of core capacities in surveillance and response covering any “illness or medical condition, irrespective of origin or source that presents or could present significant harm to humans”.
The IHR core capacity requirements for surveillance and response require Member States to develop a national (and, where possible, a sub-national) risk assessment capacity that is recognized as an integral part of the prevention, surveillance and response system. The structure and location of this capacity, which may be a dedicated team or embedded into the existing prevention, surveillance and response system, will be country-specific.
Risk assessment is a systematic process for gathering, assessing and documenting information to assign a level of risk. It provides the basis for taking action to manage and reduce the negative consequences of acute public health risks.