The Bill & Melinda Gates Foundation currently funds just over 12% of the World Health Organization’s operations, making it the second biggest donor to the WHO after the U.S. If the United States permanently withdraws funding, the foundation would become the largest single donor. The Gavi Alliance, a public-private partnership that supports vaccine development, is the WHO's next-largest donor, just ahead of the U.K. The Gates Foundation has given Gavi $4 billion since launching it in 1999.
In 2014 the WHO's then-director general, Dr. Margaret Chan, acknowledged that “my budget is highly earmarked, so it is driven by what I call donor interests.” However, the WHO is formally controlled under a UN charter by the World Health Assembly, composed of delegates from sovereign nations, who pay assessments and elect the director general.