We've made our second attempt to withdraw from the WHO. (The first one was reversed after Biden took office.) The WHO coordinates globally in instances of pandemics but also serves the public in more routine matters like establishing best practices and guidelines. And apparently air traffic control (https://time.com/7208937/us-world-health-organization-trump-withdrawal/).
I mentioned upthread that we halted a bunch of foreign aid, and some of this is also global health related: there's an immediate freeze on the distribution of HIV antiretrovirals to countries that have been receiving that form of aid (https://www.npr.org/sections/goats-and-soda/2025/01/25/g-s1-44762/pepfar-trump-hiv-foreign-aid). There are programs for other global health issues that will be similarly affected.