US President Donald Trump has signed an executive order to initiate the withdrawal of the United States from the World Health Organization (WHO).

The decision, made on his first day back in office, signals his administration’s renewed criticism of the global health body.

“Oooh, that’s a big one,” Trump remarked after signing the order in the Oval Office, one of several executive actions he enacted upon his return to the White House.

This marks the second time Trump has directed the US to pull out of the Geneva-based organisation, following his initial attempt during the Covid-19 pandemic.

That decision was later reversed by President Joe Biden. By acting on his first day in office, Trump has increased the likelihood that the withdrawal will be formalised.

“They wanted us back so badly so we’ll see what happens,” Trump said, hinting at a possible future re-engagement with the WHO.

The executive order cited several reasons for the withdrawal, including dissatisfaction with the WHO’s handling of the COVID-19 pandemic and other global health crises and concerns about its independence from political influences.

It also criticised the “unfairly onerous payments” the US has made to the organisation, which relies heavily on American funding.

During Trump’s first term, he accused the WHO of being “China-centric” and biased towards Beijing in its COVID-19 guidance.

In contrast, under Biden’s administration, the US had resumed its role as the WHO’s largest contributor, providing nearly 20% of its $6.8 billion annual budget in 2023.

Public health experts have expressed alarm over Trump’s renewed decision to withdraw, warning of potential negative impacts on both global and domestic health efforts. Critics fear the move could undermine progress in combating diseases such as malaria, tuberculosis, and HIV/AIDS.

“It’s a cataclysmic presidential decision. Withdrawal is a grievous wound to world health, but a still deeper wound to the US,” said Lawrence Gostin, a public health expert and professor at Georgetown University.

Ashish Jha, who served as a Covid-19 response coordinator under Biden, previously warned that the withdrawal could damage US leadership and scientific influence globally, saying it would “harm not only the health of people around the world but also US leadership and scientific prowess.”