"Trump has always been paranoid, hasn't he? "
Always? At least since we've known him.
The only connection between Trump and 29,000,000 of anything is what's in it for him and that's usually money (the center of his universe).
But since a second wave of Corona-19 is predicted to happen this fall and his re-election is on thin ice, he needs some last minute drama that makes him look like a Knight in shinning armor. Trump to the rescue, so to speak.
Efficacy isn't his problem. Getting over the November 3rd hump is.