i am pregnant and expecting my baby quite soon. recently i went to local CDC for some reason. and there i touched the door knob. there was a tiny wound on my thumb( quite small, about the size of a pinhole),and i am sure it was not fresh (it had been there for at least a week then). now i am worried that what if an HIV carrier had just touch that same door knob RIGHT before me, and what if his/her hand was wounded and left some blood on the knob? if all my "what ifs" really happened, am i at any risk?