The secretariat comprises the technical and administrative personnel of the organization. It is headed by a director-general, appointed by the World Health Assembly. The first director-general of WHO was Dr. Brock Chisholm of Canada. He was succeeded in 1953 by Dr. Marcolino G. Candau of Brazil and in 1973 by Dr. Halfdan T. Mahler of Denmark. Dr. Mahler served WHO for 15 years and was declared Director-General Emiritus upon his retirement in 1988. Dr. Hiroshi Nakajima of Japan was elected Director General in 1988 and re-elected to a second five-year term in 1993. Dr. Gro Harlem Brundtland succeeded him on 21 July 1998.
WHO is staffed by some 3,500 health and other experts in both professional and general service categories, working at headquarters and in the regional offices. WHO has six regional offices, each covering a major geographic region of the world. These are located in Cairo for the Eastern Mediterranean area, in Manila for the Western Pacific area, in New Delhi for the Southeast Asia area, in Copenhagen for Europe, in Brazzaville for the African area, and in Washington, DC, where the directing council of the Pan American Health Organization acts as the regional committee of WHO in the Americas.
While all work of direct assistance to individual member governments is decentralized to the regional offices, the Geneva headquarters is where the work of the regions is coordinated and worldwide technical services are organized, including collection and dissemination of information. The headquarters cooperates with the UN, the other specialized agencies, and voluntary organizations and is responsible for medical research.
WHO assistance is given in response to a request from a government. Member governments meet annually in regional committees to review and plan WHO activities for their areas. Requests are consolidated by the regional directors and forwarded to the director-general, who incorporates regional programs and their estimated costs into the overall WHO draft program and budget. The program and budget, after review by the Executive Board, are submitted to the World Health Assembly.