President Trump signed an executive order on the first day of his second term beginning the process of withdrawing the U.S. from the World Health Organization. It was among dozens of executive actions he signed after being sworn in Monday, on issues ranging from immigration to foreign policy to climate change.

Scientists and public health officials expressed concern that the move could roll back decades of gains made in fighting infectious diseases like AIDS, malaria and tuberculosis, and could weaken the world’s ability to identify and contain emerging outbreaks that could trigger future pandemics. 

The WHO came under intense criticism from Mr. Trump in 2020 for its response to the COVID-19 pandemic, which grew into a worldwide health crisis during the final year of his first term. He threatened to withdraw the U.S. at that time, although the withdrawal was not completed.

A White House statement Monday night said the U.S. would withdraw “due to the organization’s mishandling of the COVID-19 pandemic that arose out of Wuhan, China, and other global health crises, its failure to adopt urgently needed reforms, and its inability to demonstrate independence from the inappropriate political influence of WHO member states.”

It also accused the WHO of demanding “unfairly onerous payments from the United States, far out of proportion with other countries’ assessed payments.”

The order said Mr. Trump was sending a presidential letter to the United Nations secretary-general to formally notify him of the U.S. plan to withdraw — a process that takes one year, under the rules.

The World Health Organization responded by calling on the U.S. government to reconsider its decision to withdraw, saying in a statement that together they had “saved countless lives and protected Americans and all people from health threats.”

The WHO also pointed to the fact that in recent years it has made “the largest set of reforms in its history.”

A U.S. withdrawal from the organization would not only sever its funding next year — the U.S. is its largest donor — but the order also instructs the federal government’s staff to stop working with the group — something U.S. health officials do on a wide range of health issues of global concern. 

On “CBS Mornings Plus” Tuesday, CBS News chief medical correspondent Dr. Jon LaPook said health experts are already worried about the implications of pulling out of the WHO. 

“Think of the World Health Organization as the United Nations for health,” he said. “Public health experts who I’ve spoken to are concerned that we have a world leadership position with this, and if there is, for example, the next pandemic, it would help in terms of communication, to be able to be in communication with everybody around the world.”

While there are other avenues for communication, like the outreach of medical societies and individuals, LaPook said, “it’s nice to have a coordinated effort.”

contributed to this report.