I had an accidental IV stick when I was about 23, and the other person was HCV+. A bunch of us were using at my house and we kept all the brand new needles in the kitchen, well he used one and then for some reason decided to put both the front and the back cap back on (who does that?!) and then leave it on the countertop. I picked it up thinking it was new and stuck it in my arm to inject...and at the last second it occurred to me that maybe there was something wrong. So I pulled it out and asked him about it and it turned out to be his used point. I was so pissed.
But I tested clean, thank fuck. I might not have had I gone through with the whole shot.
More recently (last 2 years) I had an accidental needle stick at my acupuncturist's office when I stepped on someone else's needle that had fallen out and landed on the floor. Grrr. They said the chances of infection from anything are low with acu needles since they are so thin, are not hollow, and aren't placed below the first layer of epidermis. But I was still somewhat freaked about it until they contacted the person who was in that chair before me and confirmed their HIV and HCV neg status...and then when I tested neg. I'm much more careful now in community acupuncture places, even in licensed, accredited places its so easy for those needles to fall out and I don't know if the providers keep count of how many are in each person so they know if one goes missing.