I'm having difficulty understanding this line of reasoning. What does the authorization of ivermectin have to do with the vaccines? Xofluza, Relenza, and Tamiflu have been approved for treating influenza, and that has had no effect on the recommendation that people get their flu shots.
Someone else answered correctly saying an EUA can't be issued if an already licensed drug can help. I would further that point by saying to actually go dig up the true source of that policy on the FDA's website in your country (not someone's summary or interpretation). It's a great exercise that will leave you with some sort of ground truth in this mess.
Same as in coding, you eventually reach a point where you learn that when in doubt, you must read the source.
It's the way that emergency authorisation use works with FDA. They won't issue that if there are other safe viable treatments. These vaccines got that approval because these other options were suppressed.
