It’s official. The United States is seeking to withdraw from the World Health Organization (WHO).

Though this move had been rumored for a while, it was never abundantly clear that the Trump administration would actually move forward with it, especially on day one. To be sure, Trump tried to pull out of the WHO back in 2020. However, that decision at the time reflected the politics of the moment: Trump very transparently sought to shift blame for his own incompetent handling of the COVID-19 pandemic. His order calling for the U.S. withdrawal from the WHO was also premised on a number of falsehoods.

Apparently, though, he still holds a grudge. And this grudge may come back to harm the United States.

The executive order released on Monday night would do several things to kneecap the WHO. First, it pauses all U.S. funding to the organization. This is a huge blow. The United States is the WHO’s largest funder, accounting for nearly 18% of its $6.8 billion two-year budget, or about $1.2 billion. If other donors do not step up, the WHO will be forced to curtail much of its lifesaving work around the world. (More on that below.)

The order also demands that the Secretary of State “recall and reassign United States Government personnel or contractors working in any capacity with the WHO.” This does not apply to Americans employed directly by the WHO. However, Americans who currently support the organization in some official government capacity—everyone from scientists to logistics experts—will be forced out of their roles. While the exact number of affected officials is unclear, this move could cause serious disruptions in Geneva and at the WHO’s regional bureaus. In particular, the WHO’s regional office for the Americas, the Pan American Health Organization (PAHO), is headquartered in Washington, D.C., just a block from the State Department. I would expect significant disruptions there.

Undermining the WHO Threatens the Safety of Americans

The WHO performs a wide range of functions globally, from providing a platform for scientific collaboration and supporting health systems in lower-income countries to implementing programs that combat infectious diseases like tuberculosis, measles, and polio. Its work is based on the fundamental idea that human health is interconnected and that diseases do not respect borders. While this mission may seem idealistic, it is ultimately driven by the self-interest of the countries that support the WHO, including, historically, the United States.

There are countless examples of the WHO’s work around the world that bolster the health and welfare of Americans. All of these efforts risk being weakened, to Americans’ detriment.

Perhaps the most immediate concern is what these cuts would mean for global efforts to confront bird flu.

Also known as avian influenza or H5N1, bird flu has been spreading rapidly worldwide and has moved beyond birds to mammals, including dairy cattle. The major fear is that H5N1, a zoonotic disease (like COVID-19), could mutate into a strain capable of human-to-human transmission.

We are already seeing signs of this in the United States. On January 6, a man in Louisiana who kept a backyard chicken flock succumbed to the disease, making him the first H5N1 death reported in the United States. What’s worse, scientists at the CDC, upon examining samples, found signs that the virus has started to mutate in ways that could make human-to-human transmission easier.

The United States has a comparatively robust disease surveillance network. But not all countries do. This is where the WHO comes in. The agency is central to global efforts to strengthen surveillance systems that monitor the spread of H5N1 among animal populations and track circumstances in which it infects humans. It also provides a platform for collaboration among pharmaceutical companies on the research and production of vaccines to prevent the spread of bird flu in humans. This work is obviously urgent. As the case in Louisiana shows, it may only be a matter of time before bird flu undergoes the genetic mutations necessary to spark a pandemic.

The executive order acknowledges that there ought to be some mechanisms for international cooperation on health issues and orders the Secretary of State to “identify credible and transparent United States and international partners to assume necessary activities previously undertaken by the WHO.” In other words, the U.S. government will soon be looking for platforms to replicate— from scratch—what the WHO is already doing. This is needlessly time-consuming and potentially costly. One of the great values of the WHO is that it already lowers transaction costs (in terms of time and money) for cooperating on health issues, including the urgent case of bird flu.

Trump’s move to undermine the WHO will weaken its ability to monitor all diseases worldwide. In the case of bird flu, this funding is being pulled at exactly the same time that countries should be enhancing their cooperation on preventing a potential pandemic.

Stopping a bird flu pandemic before it starts requires cooperation through the WHO. But Trump is now making the WHO’s job much more difficult — and Americans may be worse off for it.