The US is due to officially exit the World Health Organization on Thursday, in the face of warnings it will hit both US health and global health and also in violation of a US law that requires Washington to pay the UN health agency $260 million in fees that it owes.

President Donald Trump gave notice that the US would quit the organization on the first day of his presidency in 2025, via an executive order. Under US law, it has to give one-year notice and pay all outstanding fees before departure.

On Thursday, a US State Department spokesperson said the WHO's failure to contain, manage and share information had cost the US trillions of dollars and the president had exercised his authority to pause the future transfer of any US government funds, support, or resources to the WHO.

"The American people have paid more than enough to this organization and this economic hit is beyond a down payment on any financial obligations to the organization," the spokesperson said by email.