CDC is takes a more conservative and careful approach. To answer your question, saliva carries various enzymes, capable of inactivating (making the virus incapable of infecting others) HIV instantly. Therefore minor blood in the mouth does not put you at risk. In case of a "mouthful" of blood, the person would be sitting in a clinic instead of having good time with someone. :)
CDC is not against kissing, the only thing is, they rate it as a "low risk" activity.
Thanks for the reply. That's very clear and reassuring.
I was interested in why HIV does not spread this way especially if there is blood in the mouth and also why the CDC warns against deep kissing?
It seems they are doing more harm than good by worrying a lot of people unnecessarily!
Deep kissing does not put you at HIV risk, no matter how many "what ifs" you bring to the table.