Public Health Emergency of International Concern second PHEIC was issued in May 2014 with the resurgence of polio after its near-eradication, deemed "an extraordinary event." On Friday, August 8, 2014, the World Health Organization declared its third Public Health Emergency of International Concern in response to the outbreak of Ebola in Western Africa. On Monday, February 1, 2016, the World Health Organization declared its fourth PHEIC in response to clusters of microcephaly and Guillain–Barré syndrome in the Americas, which at the time were suspected to be associated with the ongoing outbreak of Zika virus. Later research and evidence bore out these concerns; in April, the WHO
World Health Organization prevention and influence public policies in all sectors so as to address the root causes of environmental threats to health". The organization develops and promotes the use of evidence-based tools, norms and standards to support member states to inform health policy options. It oversees the implementation of the International Health Regulations, and publishes a series of medical classifications; of these, three are over-reaching "reference classifications": the International Statistical Classification of Diseases (ICD), the International Classification of Functioning, Disability and Health (ICF) and the International Classification of Health Interventions (ICHI). Other international policy frameworks produced by WHO include the International Code