The United States has formally completed its withdrawal from the World Health Organization, ending a decades-long partnership that global health experts warn could weaken outbreak detection, slow vaccine development, and disrupt international disease surveillance.

The move finalizes a decision announced by President Donald Trump at the start of his second term, severing the country’s role in the United Nations health agency after nearly 80 years. Federal officials acknowledged, however, that the separation remains incomplete, with unresolved issues including unpaid financial obligations and the loss of access to critical global health data.

According to the WHO, the United States still owes more than $130 million in outstanding dues and contributions. While Trump administration officials dispute that obligation, health experts say the funding gap has already forced the agency to scale back monitoring programs, research coordination, and emergency response capacity.

Public health specialists warn the withdrawal could significantly impair early warning systems for emerging diseases, leaving U.S. scientists and pharmaceutical companies with delayed access to outbreak intelligence that has historically guided vaccine and treatment development.

The WHO plays a central role in coordinating responses to global health threats such as Ebola, mpox, polio, and influenza. It also supports vaccination campaigns, disease tracking, and medical supply distribution in lower-income countries. Nearly every nation in the world remains a member.

Experts argue that the absence of U.S. participation weakens not only international preparedness but also domestic health security. Without WHO data-sharing networks, the U.S. risks falling behind in identifying new viral threats that often emerge abroad before spreading globally.

Administration officials say they plan to rely on direct bilateral health agreements with other countries to replace WHO-led coordination, though details on how many such arrangements exist remain unclear. Public health analysts remain skeptical, noting that many countries may be unwilling or unable to share sensitive disease data outside established multilateral frameworks.

The decision has drawn sharp criticism from medical and global health leaders, who describe the withdrawal as a strategic setback that could have long-term consequences for outbreak prevention, child health programs, and efforts to contain future pandemics.

As global health threats continue to evolve, experts warn that the U.S. exit from the WHO may limit the country’s ability to respond quickly and collaboratively when the next international health emergency emerges.