The RO was worried about conventional bacterial infections when your are immunocompromized from the treatments and have open sores in your mouth. Everyone has plenty of usually benign (in small quantities) harmful flora in their mouths. That is a bad time to get infections, but in general, since I have heard this advice before, it's a waste of words. When my mouth was bloody with mucocitis sores and I was spitting chunks of it into the sink on a daily basis, kissing was the last thing on my, and my wife's to do list.

And yes this is way easier to get than HIV, which is suprizingly difficult disease to get through any conventional means. HPV only requires the casual touch of skin against skin. HIV require a transfer of fluids, saliva, blood, semen and even then it does not live long in those environments. Where it gets a quick hold is not so much from infected blood touching you, it is infected blood getting into your blood stream. Think transfusions, think a sexual act in which surface pressure tears, no matter how small, allow it access to your blood stream. That's why HIV positive people are no longer biological pariahs in schools or society in general. I can remember when people were afraid to shake the hand of an HIV patient. This is BS. They will not give you the virus by such a simple act. Ignorance emotionally hurt many people.