On January 20, 2025, President Donald J. Trump issued an executive order signaling his intent to withdraw the United States from the World Health Organization (WHO), the United Nations agency responsible for global public health. This decision is expected to have far-reaching and negative consequences for health outcomes worldwide.

Since joining the organization in 1948, the United States has been WHO’s largest financial supporter, making it one of the agency’s most influential members. Despite its critical global role, WHO operates on a budget that is only about one-quarter the size of the U.S. Centers for Disease Control and Prevention (CDC), highlighting its limited capacity to address major health challenges on a global scale.

WHO is funded through contributions from its nearly 200 member states, with each nation’s share determined by the United Nations based on its economic standing. For the 2024–2025 period, the U.S. is assessed at $264 million, while China’s contribution is set at $181 million. In addition to these assessed dues, WHO receives voluntary contributions from member states, philanthropic foundations, and private donors. During the same period, the U.S. is projected to provide $442 million in voluntary funding—making it the organization’s largest contributor—while China is expected to contribute just $2.5 million.

Headquartered in Geneva, Switzerland, WHO maintains six regional offices and 150 country offices across the globe. Through this network, it combats epidemic and endemic diseases, sets international health standards, collects data on global health trends, facilitates scientific and policy discussions, and evaluates health challenges worldwide.

WHO also leads an expansive network of public health agencies and laboratories to monitor new disease outbreaks and gather data critical to the development of vaccines and treatments. In the United States alone, the CDC hosts 21 WHO collaborating centers, and the National Institutes of Health (NIH) hosts three. These centers focus on U.S. health priorities such as polio eradication, cancer prevention, and global health security.

The organization has been at the forefront of responses to natural disasters, including earthquakes in Afghanistan, Nepal, Syria, and Turkey, as well as catastrophic floods in Libya, Pakistan, and South Sudan. WHO has responded by deploying emergency medical teams, providing supplies, and assisting countries in managing both immediate and long-term health impacts.

U.S. funding cuts would severely affect initiatives such as childhood immunizations, polio eradication, and responses to emergencies, influenza, and other potential pandemics. WHO’s Global Influenza Surveillance and Response System processes data from around the world to monitor circulating viruses. Severing ties with the organization could limit U.S. access to critical tools for developing influenza control measures.

In 2019, WHO launched the Special Initiative for Mental Health, expanding community mental health services to 50 million people. As a result, at least 320,000 individuals—women, men, and children—received mental, neurological, or substance abuse care for the first time. WHO has also established a new Commission on Social Connection to address loneliness and social isolation, now recognized as urgent public health issues.

The commission aims to make social connection a health priority in countries of all income levels. Experts warn that a U.S. withdrawal from WHO could allow China to exert greater influence over the organization. “There is one country that’s desperate for the United States to leave the WHO, and that’s China,” noted Sen. Chris Murphy, a Connecticut Democrat, during a U.S. Senate Foreign Relations Committee hearing.

Critics also argue the move may be unlawful. The United States joined WHO through a 1948 joint resolution of Congress, which President Harry Truman cited as the legal basis for U.S. membership. As such, many observers believe that withdrawing without Congressional approval would violate U.S. law.

As an independent international public health consultant, I have carried out health-related missions in more than 50 countries for various organizations, including WHO. I have witnessed firsthand the life-saving work of WHO’s local branches in vulnerable communities across the developing world—work that is now jeopardized by funding cuts. WHO, along with other international aid agencies, has made tremendous strides in improving global health. These efforts are now at serious risk.

During the 2020 dispute between the U.S. and WHO—later reversed by President Joseph R. Biden—a group of leading global health experts wrote in The Lancet: “Health and security in the USA as globally require robust collaboration with the WHO – a cornerstone of US funding and policy since 1948. The USA cannot cut ties with the WHO without incurring major disruption and damage, making Americans far less safe.” That statement remains just as true today.