What is WHO and What Does It Do?

Explainer By Y-Trendz

The World Health Organization (WHO) is the United Nations agency responsible for coordinating international public health. For more than seven decades, it has served as the world's principal authority

on setting health standards, tracking disease outbreaks, distributing vaccines, and helping countries — rich and poor alike — build stronger health systems. Understanding what WHO is, how it is structured, and what it actually does has taken on renewed significance in recent years, as the organization has faced funding pressures, calls for reform, and the departure of its largest historical donor. This article examines WHO's origins, governance, core functions, achievements, and the challenges it currently faces.

Origins and Founding

WHO was established on 7 April 1948, a date now commemorated annually as World Health Day. Its founding charter, the WHO Constitution, was drafted in the aftermath of the Second World War, at a moment when the international community was consolidating the United Nations system and recognizing that disease knows no borders. The Constitution's opening declaration remains one of the most quoted lines in global health policy: health is "a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity," and the "enjoyment of the highest attainable standard of health is one of the fundamental rights of every human being."

The organization's first Director-General was Canadian psychiatrist Brock Chisholm, who took office in 1948. Since then, WHO has grown from a handful of founding member states into an organization comprising 194 member countries, making it one of the most universally represented bodies in the UN system.

Headquarters and Global Structure

WHO is headquartered in Geneva, Switzerland, in a building designed by Swiss architect Jean Tschumi and inaugurated in 1966. From Geneva, the organization coordinates a vast operational network consisting of six regional offices — covering Africa, the Americas, South-East Asia, Europe, the Eastern Mediterranean, and the Western Pacific — along with roughly 150 country and field offices spread across the globe. This decentralized structure allows WHO to combine centralized standard-setting with localized, on-the-ground public health response, tailoring its work to the specific epidemiological and healthcare realities of each region.

Governance: Who Runs WHO?

WHO's governance operates through a layered decision-making structure designed to balance technical expertise with member-state accountability.

The World Health Assembly (WHA) is WHO's supreme decision-making body. It is attended by delegations from all 194 member states and meets annually, typically in May, in Geneva. The Assembly's principal functions include determining the organization's overall policies, approving its programme budget, supervising financial matters, and appointing the Director-General. Because it operates by consensus among sovereign states with often divergent national interests, the Assembly's decision-making can be slow and, at times, diluted — a structural feature that critics have pointed to as a source of institutional inertia during crises.

The Executive Board consists of 34 members technically qualified in the field of health, each designated by a member state elected to serve on the Board. The Board gives effect to the decisions and policies of the World Health Assembly, and it plays a central role in preparing the agenda for Assembly sessions, including nominating candidates for the position of Director-General.

The Director-General is WHO's chief technical and administrative officer, overseeing the organization's international health work and acting as its principal spokesperson on global health matters. The Director-General is nominated by the Executive Board and formally appointed by the World Health Assembly, serving a five-year term that is renewable once. The current Director-General, Dr Tedros Adhanom Ghebreyesus of Ethiopia, was first appointed in 2017 and began his second term in August 2022, a term set to conclude in August 2027. Beneath the Director-General, a team of deputy and assistant directors-general oversee specific technical divisions, ranging from communicable and noncommunicable diseases to emergency preparedness and health systems strengthening.

Core Functions of WHO

WHO's mandate is broad, but its activities generally fall into several core categories.

1. Setting international health standards and norms. WHO develops and publishes technical guidelines, treatment protocols, and classification systems used by health ministries and clinicians worldwide. Perhaps the most widely used of these is the International Classification of Diseases (ICD), the global standard for diagnosing and coding diseases, which underpins everything from clinical practice to insurance systems and national health statistics. WHO also maintains the Model List of Essential Medicines, a reference document that guides countries in prioritizing which drugs should be affordable and available in public health systems.

2. Monitoring and responding to disease outbreaks. WHO operates a global surveillance network that tracks the emergence and spread of infectious diseases, from seasonal influenza to novel pathogens. Under the International Health Regulations — a legally binding framework agreed upon by member states — WHO has the authority to declare a "Public Health Emergency of International Concern," a designation that mobilizes international resources and coordination. This mechanism has been invoked for outbreaks including Ebola, Zika virus, and, most notably, COVID-19.

3. Coordinating emergency health response. In humanitarian crises, natural disasters, and conflict zones, WHO works alongside national governments and partner agencies to deliver medical supplies, deploy health workers, and support disease prevention among displaced populations. This work is often carried out in coordination with agencies such as UNICEF and the International Committee of the Red Cross.

4. Supporting immunization and disease eradication campaigns. WHO has played a central role in some of history's most significant public health achievements. It led the global campaign that eradicated smallpox in 1980 — the only human disease ever fully eradicated — and it continues to lead the decades-long effort toward polio eradication, which has reduced global polio cases by more than 99% since the initiative began. WHO also co-leads major vaccination programmes for diseases such as measles, yellow fever, and cholera, often in partnership with organizations like Gavi, the Vaccine Alliance.

5. Strengthening health systems. Beyond emergency response, WHO provides technical assistance to help countries build more resilient, accessible healthcare infrastructure — training health workers, advising on health financing models, and supporting the expansion of primary care, particularly in low- and middle-income countries.

6. Conducting and disseminating health research. WHO regularly publishes global health reports, including the World Health Statistics series and disease-specific data on conditions ranging from tuberculosis and malaria to noncommunicable diseases like diabetes and cardiovascular disease. This research underpins policy decisions made by governments and international donors alike.

7. Advocacy on social determinants of health. WHO has increasingly focused on the broader factors that shape health outcomes — nutrition, sanitation, tobacco control, mental health, climate change, and health equity — arguing that sustainable improvements in population health require addressing conditions well beyond the walls of a hospital or clinic.

Funding and Financial Structure

WHO's budget is financed through two main streams: assessed contributions, which are mandatory dues paid by member states based on a formula tied to national wealth and population (similar to UN dues), and voluntary contributions from governments, philanthropic foundations, and private donors, which today make up the larger share of WHO's overall budget. This heavy reliance on voluntary, often earmarked funding has long been a point of institutional vulnerability, since donors can direct funds toward specific programmes of their choosing, leaving WHO with limited flexibility to address emerging or under-funded health priorities.

Recent Challenges: The COVID-19 Legacy and the U.S. Withdrawal

WHO's handling of the COVID-19 pandemic became one of the most consequential and contested episodes in its history. The organization faced criticism over the speed and transparency of its initial response, including questions about its coordination with Chinese authorities in the pandemic's early weeks. These criticisms fed into a broader push for institutional reform, and they directly informed one of the most significant developments in WHO's recent history: the withdrawal of the United States.

On his first day back in office in January 2025, President Donald Trump signed an executive order initiating a one-year process to withdraw the United States from WHO, citing the organization's handling of COVID-19, its perceived failure to implement urgently needed reforms, and concerns about its independence from political influence among member states. Under WHO's constitutional withdrawal provisions, the process required a one-year notice period. That process concluded on 22 January 2026, when the U.S. Department of Health and Human Services and the State Department formally confirmed the completion of the United States' exit from the organization. All U.S. government funding to WHO has since been terminated, American personnel have been withdrawn from WHO headquarters and field offices, and Washington has ceased participation in WHO governance structures and technical committees, including negotiations on a proposed global pandemic treaty.

The financial implications of this withdrawal are substantial. The United States had historically been WHO's largest single donor, contributing roughly 18% of the organization's funding — an estimated $261 million between 2024 and 2025 alone — ahead of China, which contributed a smaller though still significant share. Health policy experts have warned that the loss of America's top-donor role could hamper WHO's capacity to respond to ongoing global health threats, including tuberculosis, HIV/AIDS, and future pandemic preparedness, while also raising questions about which countries might step in to fill the resulting leadership and funding vacuum.

In parallel, WHO has been navigating its own internal reform process, including new accountability procedures approved by the World Health Assembly in 2025 for investigating allegations of misconduct within the organization, alongside a broader restructuring of its Geneva-based leadership team aimed at improving efficiency amid tightening budgets.

Looking Ahead

WHO's next Director-General election process is already underway, with member states invited to submit candidatures beginning in April 2026 ahead of a formal nomination and vote expected at the Eightieth World Health Assembly in May 2027. The organization enters this transition period at a genuinely pivotal moment: stripped of its largest historical funder, under pressure to demonstrate greater transparency and independence, and tasked with proving — to a more skeptical international community — that a coordinated global health authority remains indispensable in an era of pandemics, climate-linked disease, and widening health inequities.

Despite the turbulence, WHO's core mission has not changed since 1948: to act as the directing and coordinating authority on international health work, so that health emergencies are met with a global response rather than a fragmented, country-by-country scramble. Whether the organization can adapt its funding model, governance, and credibility to meet that mission in a changed geopolitical landscape will likely define its next chapter.

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This article is based on information from the World Health Organization, the U.S. Department of Health and Human Services, the CDC, Al Jazeera, the Congressional Research Service, and CSIS, as of July 24, 2026.