Short answers, pulled from the story.
The WHO's constitution came into force on the 7th of April 1948, when it was ratified by the 26th member state. The organization formally began its work on the 1st of September 1948, though its real operational momentum arrived in 1951 after a significant infusion of financial and technical resources.
Smallpox was declared eradicated by a Global Commission in 1979, making it the first disease in history to be eliminated by human effort. The WHO intensified the campaign in 1967, contributing $2.4 million annually and building a surveillance network to address widespread underreporting, at a time when 2 million people were dying of smallpox each year.
The United States formally withdrew from the WHO on the 22nd of January 2026, one year after President Donald Trump signed an executive order initiating the process on the 20th of January 2025. The stated reason was the organization's alleged mishandling of the COVID-19 pandemic. The US also disputed owing approximately $260 million in outstanding fees, and the administration said it would not rejoin or participate as an observer.
The WHO is funded through assessed contributions from member states, voluntary contributions, and private donors. In 2020-21, the largest contributors were Germany, the Bill and Melinda Gates Foundation, the United States, France, the United Kingdom, and the European Commission. In 2024, the Gates Foundation was the largest private contributor, funding 10% of the budget.
G. Brock Chisholm was appointed the WHO's first director-general. He had previously served as executive secretary and founding member during the organization's planning stages. Andrija Stampar served as the first president of the World Health Assembly, which concluded its first meeting on the 24th of July 1948.
Szeming Sze, a delegate from the Republic of China, first raised the idea of an international health organization at the 1945 United Nations Conference on International Organization, consulting Norwegian and Brazilian delegates in the process. After a resolution failed, he and other delegates lobbied for a declaration, which passed and called for an international health conference, directly leading to the WHO's creation.