World Health Organization (WHO), French Organisation Mondiale de la Santé, specialized agency of the United Nations (UN) established in 1948 to further international cooperation for improved public health conditions. Although it inherited specific tasks relating to epidemic control, quarantine measures, and drug standardization from the Health Organization of the League of Nations (set up in 1923) and the International Office of Public Health at Paris (established in 1907), WHO was given a broad mandate under its constitution to promote the attainment of “the highest possible level of health” by all peoples. WHO defines health positively as “a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.” Each year WHO celebrates its date of establishment, April 7, 1948, as World Health Day.
With administrative headquarters in Geneva, governance of WHO operates through the World Health Assembly, which meets annually as the general policy-making body, and through an Executive Board of health specialists elected for three-year terms by the assembly. The WHO Secretariat, which carries out routine operations and helps implement strategies, consists of experts, staff, and field workers who have appointments at the central headquarters or at one of the six regional WHO offices or other offices located in countries around the world. The organization is led by a director general nominated by the Executive Board and appointed by the World Health Assembly. The director general is supported by a deputy director general and multiple assistant directors general, each of whom specializes in a specific area within the WHO framework, such as family, women’s, and children’s health or health systems and innovation. The organization is financed primarily from annual contributions made by member governments on the basis of relative ability to pay. In addition, after 1951 WHO was allocated substantial resources from the expanded technical-assistance program of the UN.