The World Health Organization acknowledged Tuesday that the US freeze on foreign aid funding has hit vital global health programmes but vowed to find a way to keep delivering to those in need.

The United Nations health agency said it was still too early to determine the full impact of the freeze on foreign aid spending by the United States — traditionally the world's largest aid donor.

But WHO spokeswoman Margaret Harris admitted that some programmes had clearly been affected, including the global measles surveillance network, which had been 100-percent funded by the United States.

On measles, "there is a big shortfall", she told reporters in Geneva.

"We're not going to let it collapse," she insisted, adding though that "finding a way to keep it going is of course challenging."

Janet Diaz, head of the Safe Scalable Care unit at WHO's emergencies programme, said the response to an ongoing Ebola outbreak in Uganda had been hit by the US aid freeze.

"WHO has had to step up and cover areas it usually doesn't support," she said, pointing to "biological sample transport and logistics and the deployment of surveillance teams to points of entries."

The agency, she said, had released $3.4 million from its emergencies contingency fund to help boost support for the government-led response, she said.

Diaz meanwhile said that infection prevention and sanitation efforts in emergencies were also affected.

WHO, she said, was now looking at "how can we deliver with less" and how can we "optimise partnerships, collaborations with other agencies to be able to deliver and find other donors."

Not giving up

Regardless of how many programmes are affected, Harris insisted that WHO would find a way to keep providing the assistance needed.

"We won't let the people of the planet down," she said. 

"We're not going to just sit there and weep. We're not going to just give up."

US President Donald Trump signed an executive order on his first day in office on January 20, demanding a 90-day freeze on all US foreign aid to give his administration time to review overseas spending.

But he has since unleashed sweeping cuts that rights groups say have already hurt millions around the world.

Trump's cost-cutter-in-chief, tech billionaire Elon Musk, insisted Monday on X, which he owns, that "no one has died as a result of a brief pause to do a sanity check on foreign aid funding. No one."

Asked about that assertion, Harris stressed Tuesday that it was "much to early to make those kinds of assessments."

"You wouldn't be able to quantify anything like that for quite some time from now," she said.

"You wouldn't be able to say 'yes', you wouldn't be able to say 'no', because you'd have to do a proper evaluation."