The eradication of polio as a global health threat may be delayed unless US funding cuts potentially totalling hundreds of millions of dollars over several years are reversed, a senior World Health Organisation (WHO) official has warned.

The WHO works with groups such as Unicef and the Gates Foundation to end polio. The planned withdrawal of the United States from WHO has impacted efforts, including stopping collaboration with the US Centres for Disease Control and Prevention.

Last week, Unicef’s polio grant was terminated as the State Department cut 90 per cent of USAID’s grants worldwide to align aid with President Donald Trump’s ‘America First’ policy.

In total, the partnership is missing $133 million from the US that was expected this year, said Hamid Jafari, director of the polio eradication programme for the WHO’s Eastern Mediterranean region. The area includes two countries where a wild form of polio is spreading: Afghanistan and Pakistan.

“If the funding shortfall continues, it may potentially delay eradication … it may lead to more children getting paralysed,” he said, adding that the longer it took to end polio, the more expensive it would be.

He added that the partners were working out ways to cope with the funding shortage, which will largely impact personnel and surveillance, but hoped the US would return to funding the fight against polio.

“We are looking at other funding sources … to sustain both the priority staff and priority activities,” he said, adding that vaccination campaigns in both Afghanistan and Pakistan would be protected.

Unicef did not respond to requests for comment, and a spokesperson for the Gates Foundation reiterated that no foundation could fill the gap left by the US.

Saudi Arabia gave $500m to polio eradication last week.

The partnership already faces a $2.4 billion shortfall to 2029, as it accepted last year that it would take longer and cost more to eradicate the disease than hoped.