GENEVA, Sept 7, 2025 (BSS/AFP) - World Health Organization chief Tedros Adhanom Ghebreyesus on Sunday defended the United States' premier public health agency, which has been left reeling by US President Donald Trump's administration.

"No institution is perfect and continued improvements are always needed to make sure the latest science and evidence is applied to emerging challenges in real time. But the work of the US CDC has been invaluable and must be protected!" he said in a statement.

The US Centers for Disease Control and Prevention (CDC) has been plunged into turmoil after Trump's government ousted its director, Sue Monarez, just weeks into her job.

Monarez had clashed with US Health Secretary Robert F. Kennedy Jr., who had fired scientists and overhauled the nation's vaccine policies.

Tedros said the CDC had "long been a centre of excellence", with many countries emulating it.

The WHO, he said, had a "close and long standing partnership" with the CDC.

The United States, which had been the biggest donor to the WHO, is in the process of pulling out of the UN health agency under a January executive order signed by Trump. The process to fully withdraw takes one year.

Monarez reportedly refused to commit to supporting Kennedy's vaccination policy changes. Her ouster triggered the resignation of at least four top CDC officials, deepening the chaos in the US agency.

Since taking office, Kennedy has restricted who can receive Covid-19 shots, cut off federal research grants for the mRNA technology credited with saving millions of lives, and announced new research on debunked claims about autism.