There is controversy regarding whether the US can immediately withdraw from the WHO. Here is the answer.
The answer is YES, unless Congress acts to require its ratification of the process. The President can certainly stop his executive agencies from interacting with the WHO immediately.
For the US, withdrawal can be accomplished either by invoking the reservation the US added when it joined the WHO by signing its Constitution in 1946, or by citing provisions in the Vienna Convention on Treaties.
a) Using the reservation requires a year’s notice, which Trump already gave, and paying up our dues. Professor Boyle and I believe this would allow an immediate departure. This reservation language could be found on the State Department website, and I believe I have previously provided a link to it, but today it is difficult to find there, as the site is in flux. I could not find it on the WHO website either. But a wonderful colleague found it in the US Code:
https://uscode.house.gov/statviewer.htm?volume=62&page=441#
However, the Congressional Research Service studied the issue of the mechanics of leaving the WHO when Trump gave notice to the WHO in July 2020. You can read the entire report, or the relevant section below.
b) Alternatively, the US could leave by citing the Vienna Convention, from which I have screenshot the relevant 2 provisions, in the article below, which I wrote in late 2023. There is no particular time limit, nor are there other requirements to be met if the United States uses this process.
Now if we would just get out of the UN......
Given the consequences of subjecting ourselves to the management of a pandemic by the WHO, I think we'd be nuts to give a squat what the so-called law says about it. It's not like the Federal government and State governments don't violate the original intent of their respective constitutions ALL THE TIME already. Why become "retentive" about "legality" when our very lives and health are on the line? They strain at gnats and swallow camels. Despicable.