The FDA once concluded Ivermectin was safe & effective for humans. After 23 years, they've changed their minds. https://www.fda.gov/consumers/consumer-updates/why-you-should-not-use-ivermectin-treat-or-prevent-covid-19

The NIH once praised it as a wonder drug, while it was profitable for them: But now It's more profitable to condemn it.

Maybe because they co-own the patent rights for the vaccine? Just a WILD guess. https://www.axios.com/moderna-nih-coronavirus-vaccine-ownership-agreements-22051c42-2dee-4b19-938d-099afd71f6a0.html

https://www.documentcloud.org/documents/6935295-NIH-Moderna-Confidential-Agreements.html#document/p105/a568569