Rather fits in with the "Matrix" humans as batteries schtick doesn't it? No wonder Q has quoted the scriptire about the full armor of God!
I think visible demons are possibly the most vulnerable.
Maybe but if we all simultaneously treated ourselves it might die out. If it didn't we'd have a pretty good idea of who was spreading this and from where.
If you mean you won't develop antibodies, you are correct. However, it does not necessarily mean you are not immune. Innate immunity is a thing, too.
Plus letting vulnerable people take CHQ when there is community spread could be.done.