The United States is set to officially withdraw from the World Health Organization (WHO) on Thursday, raising concerns about potential impacts on both U.S. and global health.

The move also comes amid warnings that it may violate U.S. law requiring Washington to pay $260 million in outstanding fees to the U.N. health agency.

President Donald Trump announced the U.S. would leave WHO on the first day of his presidency in 2025 via executive order. U.S. law mandates a one-year notice and full payment of outstanding fees before formal withdrawal.

According to WHO, the U.S. has yet to pay its dues for 2024 and 2025.

A State Department spokesperson defended the decision, citing what it described as WHO’s failures to contain, manage, and share information during global health crises. “The American people have paid more than enough to this organization,” the spokesperson said, noting that the president had paused future U.S. funding to the WHO.

WHO Director-General Tedros Adhanom Ghebreyesus has repeatedly urged the U.S. to reconsider. “Withdrawing from the WHO is a loss for the United States, and it’s a loss for the rest of the world,” he said at a recent press briefing.

Legal experts have also weighed in. Lawrence Gostin, founding director of the O’Neill Institute for Global Health Law, described the move as a clear violation of U.S. law, though he suggested enforcement is unlikely.

The U.S. departure has already sparked a budgetary crisis at WHO, the U.N.’s main health agency, which traditionally relies on Washington for about 18% of its funding. The organization has scaled back work, cut management positions by half, and expects to reduce staff by roughly a quarter this year.

Global health authorities warned that the move could have wide-reaching consequences, potentially hampering disease response and coordination efforts worldwide. Bill Gates, chair of the Gates Foundation, told Reuters in Davos that he does not expect the U.S. to return in the short term, but emphasized the continued global need for WHO and the world.

“The U.S. withdrawal from WHO could weaken the systems and collaborations the world relies on to detect, prevent, and respond to health threats,” said Kelly Henning, public health program lead at Bloomberg Philanthropies, a U.S.-based non-profit.

Reuters