The WHO is infuriating but it's in our interest to remain a member

Yes. The benefits are clear. Disease surveillance, such as monitoring populations for worrying signs of outbreaks or testing animals for potential zoonotic infections that could “jump” to humans, requires round the clock and round the world monitoring. The U.S. could not do it on its own; it requires extensive NGO networks, resources and personnel that only an international organization like the WHO can provide.

Furthermore, American biomedical research is deeply integrated with the WHO. The U.S. has 83 collaborating centers with the WHO, including the Fred Hutchinson Cancer Research Center in Seattle, St. Jude Children’s Research Hospital in Memphis and Johns Hopkins University in Baltimore. One example of the important collaborative work is the twice-annual decision to determine which strains will make up the northern and southern hemisphere seasonal influenza vaccines. As Stat News details, if the U.S. leaves the WHO, it is unclear to what extent organizations like the Centers for Disease Control and Prevention would participate or to what extent they can continue similar work on their own or with other countries through different channels. Collecting intelligence from other countries is vital to protecting not just global public health but the health of American citizens – which, in turn, helps protect the health of the economy.

Critics might suggest that these functions could be served by another organization, but it’s unclear who that could be. Scientific research is an international endeavor and, hence, benefits from the existence of international bodies that facilitate collaboration. The Bill & Melinda Gates Foundation, which has a similar mission to that of the WHO, was the latter’s second-largest source of funding in the 2018-19 budget cycle. (The U.S. was the largest.) Obviously, if the Gates Foundation is willing to send more money to the WHO than any nation on the planet except the U.S., it clearly sees a tangible benefit. Besides, any organization that could grow large enough to take the place of the WHO eventually will succumb to the same problems of sclerosis and ineptitude. It’s like Murphy’s Law applied to humans in large groups.