In simple terms
The World Health Organization, or WHO, is the United Nations agency responsible for international public health, working to coordinate responses to disease outbreaks, set global health standards, and support health systems around the world. [1]
How it works
WHO was established in 1948 as a specialized agency of the United Nations, headquartered in Geneva, Switzerland, with regional offices around the world. [1] Member countries fund and govern the organization through its World Health Assembly, which sets policy and priorities each year. WHO’s work spans a wide range of activities: tracking and responding to disease outbreaks, publishing technical guidelines that countries can adopt into national health policy, coordinating vaccination campaigns, and setting international standards for issues such as vaccine safety and tobacco control. [2]
When an outbreak is serious enough, WHO can declare a Public Health Emergency of International Concern, its highest level of alert, intended to mobilize coordinated action and resources from governments and health agencies worldwide. [1]
Why it matters
WHO’s coordinated vaccination campaign led to the global eradication of smallpox, declared successful in 1980, still the only human disease ever eradicated worldwide through vaccination, and a frequently cited example of what international health cooperation can achieve. [2]
Where you’ll see it
- Global vaccination campaigns and immunization guidelines
- Outbreak response coordination during epidemics and pandemics
- International health regulations that shape border and travel health policy
- Published statistics and reports tracking global disease burden
Example
During a new disease outbreak, WHO gathers reports from affected countries, issues technical guidance on containment, and can formally declare a global health emergency to coordinate international funding and response.
Often confused with
National health agencies, such as the Centers for Disease Control and Prevention in the United States, operate within a single country; WHO coordinates across all of its member countries and has no authority to enforce policy directly within any nation’s borders.
Key facts
- The World Health Organization was established in 1948 as a specialized agency of the United Nations, headquartered in Geneva, Switzerland.1
- WHO led the global campaign that eradicated smallpox, declared successful in 1980, the only human disease eradicated worldwide through vaccination to date.2
- WHO can declare a Public Health Emergency of International Concern, its highest level of alert, to mobilize a coordinated global response to an outbreak.1
- WHO sets international standards and guidelines on topics ranging from vaccine safety to tobacco control, which member countries can adopt into national policy.2
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Quick checkWhat is the WHO's highest-level formal alert for a global health crisis called?Show answer
A Public Health Emergency of International Concern, the organization's most serious designation, used to mobilize a coordinated international response to an outbreak.
Sources
- World Health Organization. About WHO. Undated (accessed 1 November 2026)
- Encyclopaedia Britannica. World Health Organization. Undated (accessed 1 November 2026)
Editorially reviewed by Last reviewed November 1, 2026Researched and drafted with AI assistanceReport an issue