How the WHO Works—and What Happens When Countries Leave
The World Health Organization coordinates global health efforts for 194 member states. Here is how it is structured, funded, and what happens when a country decides to withdraw.
A Global Health Authority Born From War
The World Health Organization was established in 1948, rising from the ashes of World War II with a sweeping mandate: achieve the highest possible level of health for every person on Earth. Its constitution, which came into force on April 7 of that year—now celebrated annually as World Health Day—defines health not merely as the absence of disease but as "a state of complete physical, mental and social well-being."
Headquartered in Geneva, Switzerland, the WHO today counts 194 member states and operates through six regional offices and more than 150 country-level field offices. Its fingerprints are on some of modern medicine's greatest triumphs, from the eradication of smallpox in 1980 to the ongoing global push to eliminate polio.
How the WHO Is Governed
The World Health Assembly (WHA) is the supreme decision-making body. Delegates from all member states meet annually in Geneva to set priorities, approve the budget, and elect the Director-General, who serves a five-year term. Below the Assembly sits the Executive Board—34 health experts nominated by member states—which steers the agenda between sessions.
Each of the six WHO regions (Africa, the Americas, Southeast Asia, Europe, the Eastern Mediterranean, and the Western Pacific) elects its own regional director and tailors programmes to local health challenges. This decentralised structure lets the organisation respond to threats ranging from Ebola outbreaks in West Africa to air-quality crises in South Asia.
Follow the Money: How the WHO Is Funded
The WHO runs on two revenue streams. Assessed contributions are membership dues calculated as a share of each country's gross domestic product and approved by the Assembly every two years. These dues currently cover less than 20 percent of the total budget. The rest comes from voluntary contributions—donations from governments, philanthropic foundations like the Bill & Melinda Gates Foundation, and private-sector partners.
That lopsided funding model has long drawn criticism. Because most money is earmarked by donors for specific programmes, the WHO has limited flexibility to redirect resources toward emerging priorities. In 2022, member states voted to gradually raise assessed contributions to cover 50 percent of the core budget by the 2030–2031 cycle. In 2025, they approved a further 20 percent increase along with a 2026–2027 budget of US$4.2 billion.
What Happens When a Country Withdraws
Unlike many international treaties, the WHO Constitution contains no withdrawal clause. The founding delegates intentionally omitted one, believing universality was essential to global health. In legal terms, the Vienna Convention on the Law of Treaties provides default rules, generally requiring the consent of other parties for a withdrawal to take effect.
The United States is a special case. When Congress authorised U.S. participation in the WHO in 1948, it embedded a domestic right to withdraw upon one year's notice and fulfilment of outstanding financial obligations. President Trump invoked that mechanism in January 2025, and the withdrawal took effect in January 2026—making the U.S. the first major power to leave the organisation.
Argentina followed a similar path, with its exit becoming official in March 2026 under President Javier Milei. Both governments cited concerns over the WHO's handling of the COVID-19 pandemic and a perceived lack of reform.
Why It Matters
When a top contributor exits, the ripple effects are significant. The United States had provided roughly 12 to 15 percent of the WHO's total funding. Its departure threatens programmes addressing HIV/AIDS, tuberculosis, malaria, and maternal health—particularly in Africa, where WHO-funded initiatives are a lifeline for fragile health systems.
Withdrawal also severs participation in critical surveillance networks. The Global Influenza Surveillance and Response System, which tracks flu strains and guides annual vaccine formulations, loses a major data-sharing partner when a country steps away. Experts at Johns Hopkins have warned that the consequences "will be a slow bleed"—not immediately visible, but increasingly difficult to reverse.
At the same time, vacuums create opportunities. Countries such as China, India, and Saudi Arabia have signalled willingness to increase their influence within the organisation, potentially reshaping the WHO's priorities for decades to come.
