Ivermectin tablets are approved by the FDA to treat people with intestinal strongyloidiasis and onchocerciasis, two conditions caused by parasitic worms. In addition, some topical (on the skin) forms of ivermectin are approved to treat external parasites like head lice and for skin conditions such as rosacea.
Here's the FDA's own website: https://archive.is/DBnG5
Ivermectin safe enough to use for head lice, too risky to use if someone's dying of a respiratory infection. Clown...Fucking...World...