President Donald Trump signed an executive order on Monday evening withdrawing the United States from the World Health Organization, a move some public health experts say will put the nation at a major disadvantage.

In the order, Trump accused the WHO of "mishandling" the COVID-19 pandemic, not adopting "urgently needed reforms" and being politically influenced by other member states.

The president also said the withdrawal was about "being ripped off."

"Everybody rips off the United States and that's it -- it's not going to happen anymore," Trump said Monday night when asked by a reporter about his experience leading the country during the COVID-19 pandemic and the importance of the WHO to mount a global response to pandemics.

The text of the executive order describes an "unfair" demand of "onerous payments from the United States, far out of proportion with other countries' assessed payments."

"China, with a population of 1.4 billion, has 300 percent of the population of the United States, yet contributes nearly 90 percent less to the WHO," the executive order reads.

Trump's executive order is an attempt to finish a process he began during the last months of his first term. The president temporarily slashed funding and signed an executive order in July 2020 removing the U.S. from the WHO but, because withdrawal requires a one-year notice, former President Joe Biden reversed the decision upon taking office in January 2021.

Public health experts who spoke to ABC News said they worry the withdrawal from the WHO will put the U.S. at a disadvantage when it comes to responding to health crises at home and abroad.

"The U.S. withdrawal from the WHO is really disappointing news. It's a strategic mistake in so many ways for us as a country," Dr. Daniele Fallin, dean of the Rollins School of Public Health at Emory University in Atlanta, told ABC News.

"Not being part of the WHO means not only do we threaten the health of Americans and our fellow humans across the globe, but we also lose our stature as a leader in global health, and I'm very concerned about that," she added.

Here's what experts said would be the implications of the U.S. leaving the WHO:

U.S. could miss early warning signs of disease

Removing the U.S. from the WHO could hamper efforts to address current public health issues, such as bird flu, the experts said.

Human cases have been diagnosed across the country since April 2024, with 67 confirmed as of Monday, according to the Centers for Disease Control and Prevention.

The CDC and other public health officials say there is currently no evidence of human-to-human transmission and the risk to the general public is low. However, federal health officials have prepared millions of vials of an available bird flu vaccine as a precautionary measure, in case it becomes necessary.

Last year, the WHO announced it had launched an initiative to help accelerate the development of a human bird flu vaccine using messenger RNA (mRNA) technology.

No longer being part of the WHO could mean losing the ability to collaborate on disease preparedness and response, as well as the ability to exchange information about emerging threats to public health, the experts said.

The U.S. also majorly contributes to the WHO's work, including collaborations with the CDC and the National Institutes of Health on issues including cancer prevention and global health security.

"I think about the WHO as a network of countries around the world that inform and protect each other when health issues are emerging, whether they're health issues entering into the United States, or whether the health issue is going outside the United States," Dr. Perry Halkitis, dean of the Rutgers School of Public Health in New Jersey, told ABC News. "And so, it is disadvantageous for people, and is disadvantageous for the United States, [who need] access to relevant, timely, important information."

U.S. could play lesser role in responding to global health crises

WHO Director-General Dr. Tedros Adhanom Ghebreyesus responded to the withdrawal announcement in a statement early Tuesday morning, expressing "regret" to hear the news.

"For over seven decades, WHO and the USA have saved countless lives and protected Americans and all people from health threats," his statement read, in part. "Together, we ended smallpox, and together we have brought polio to the brink of eradication. American institutions have contributed to and benefited from membership in WHO."

Public health experts said not being part of the WHO when those initiatives were being conducted -- and, in some cases, are still being conducted -- would have been detrimental to making progress at home and abroad.

Thomas Bollyky, director of the global health program at the think tank Council on Foreign Relations, described the executive order removing the U.S. from the WHO as "an enormous mistake."

He said he's worried because it comes at the same time as another executive order Trump signed putting a 90-day pause on all foreign aid spending.

"Many U.S. global health programs fund the ongoing treatment of individuals for malaria or for HIV/AIDS," he told ABC News. "A 90-day pause could be significantly disruptive to the operation of those programs, and it is not entirely certain how the strategy review that will occur during that time will affect global health programs moving forward."

"The WHO is not a perfect institution, but it plays an irreplaceable role in global outbreak response and, by withdrawing this action, reduces the ability of the United States to positively influence that response to outbreak. It makes Americans less safe," Bollyky added.

Tesla CEO and tech billionaire Elon Musk, whom Trump tapped to head the newly formed Department of Government Efficiency (DOGE), responded to the WHO's statement on X with a kiss-face emoji on Tuesday morning.

ABC News' Cheyenne Haslett contributed to this report.