The principal organs of WHO are the World Health Assembly, the Executive Board, and the secretariat, headed by a director-general.
All WHO members are represented in the World Health Assembly. Each member has one vote but may send three delegates. According to the WHO constitution, the delegates are to be chosen for their technical competence and preferably should represent national health administrations. Delegations may include alternates and advisers. The assembly meets annually, usually in May, for approximately three weeks. Most assemblies have been held at WHO headquarters in Geneva. A president is elected by each assembly.
The World Health Assembly determines the policies of the organization and deals with budgetary, administrative, and similar questions. By a two-thirds vote, the assembly may adopt conventions or agreements. While these are not binding on member governments until accepted by them, WHO members have to "take action" leading to their acceptance within 18 months. Thus, each member government, even if its delegation voted against a convention in the assembly, must act. For example, it must submit the convention to its legislature for ratification. It must then notify WHO of the action taken. If the action is unsuccessful, it must notify WHO of the reasons for nonacceptance.
In addition, the assembly has quasi-legislative powers to adopt regulations on important technical matters specified in the WHO constitution. Once such a regulation is adopted by the assembly, it applies to all WHO member countries (including those whose delegates voted against it) except those whose governments specifically notify WHO that they reject the regulation or accept it only with certain reservations.
WHO is empowered to introduce uniform technical regulations on the following matters:
The assembly, at its first session in 1948, adopted World Health Regulation No. 1, Nomenclature with Respect to Diseases and Causes of Death. This regulation guides member countries in compiling statistics on disease and death and, by providing for a standardized nomenclature, facilitates their comparison. World Health Regulation No. 2 deals with quarantinable diseases.
Each year, the assembly doubles as a scientific conference on a specific topic of worldwide health interest, selected in advance. These technical discussions are held in addition to other business. They enable the delegates, who as a rule are top-ranking public health experts, to discuss common problems more thoroughly than formal committee debates would permit. Governments are asked to contribute special working papers and studies to these discussions and, if practicable, to send experts on the matters to be discussed with their delegations.
The World Health Assembly may elect any 32 member countries (the only rule being equitable geographical distribution) for three-year terms, and each of the countries elected designates one person "technically qualified in the field of health" to the WHO Executive Board. The countries are elected by rotation, one-third of the membership being replaced every year, and may succeed themselves. Board members serve as individuals and not as representatives of their governments.
The Executive Board meets twice a year, for sessions of a few days to several weeks, but it may convene a special meeting at any time. One of its important functions is to prepare the agenda of the World Health Assembly. The WHO constitution authorizes the board "to take emergency measures within the functions and financial resources of the Organization to deal with events requiring immediate action. In particular, it may authorize the director-general to take the necessary steps to combat epidemics and to participate in the organization of health relief to victims of a calamity."