Swapping body fluids is also a strain on the immune system. Everyone you’ve had sex with, including everyone they had sex with ad infinitum, ad nauseum... it can literally go into the thousands and beyond. Your immune system has a great chore to perform and will breakdown because of the overload.
Stay virginal, and marry a virgin, and do not go astray. Just as the Lord intended.
This is not only a microbial cloud though. Our exfoliated and extruded cells, containing our DNA, also circulate in it.
We inevitably take into our bodies the DNA (as well as the microbials) from the auras of other people, some in minute quantity, some in larger quantity.
DNA is durable. Though much of it, perhaps most of it, will never reach our tissues, some will.