The international agency, part of the United Nations, was founded in 1948 and includes 194 countries working together to fight the world’s toughest public health problems. It is the cornerstone of global health efforts, with a multinational staff fighting both communicable diseases—like COVID-19, Zika, and HIV—and chronic conditions, such as heart disease, diabetes, and cancer.

WHO also works to fight malnutrition, deliver vaccines, and provide assistance and technical guidance to people in poor and battle-scarred regions of the world. Its biennial budget is $6.8 billion. The U.S. is among the largest donors.

Over the years, WHO has worked to eradicate smallpox, reduce worldwide polio cases by 99%, and greatly reduce the prevalence of malaria and trachoma, the world’s leading cause of blindness.