It costs a ton of money to bring a treatment to market, and this one has roughly zero commercial value. Presumably once in the world it would naturally spread just by people kissing or whatever.
I don't think it's totally impossible that this really works and everyone gave up on it.
But I'd probably still put my money on this not really working (or having unwelcome side effects) and people quietly shutting down the project without publicly documenting the issues.
