Can I contract HIV in a single sexual encounter with vaginal sex and?
Yes, you can. But the odds of that happening are only about 1 in 1000 even if the man is HIV-positive and is not taking anti-retroviral medication. HIV is actually very difficult to get, and is much less contagious than most people think it is. HIV Risk Behaviors However, the odds do go up if the sex was very rough, and they also go up if either you or he had some other STD such as herpes or chlamydia or gonorrhea. But if the man is HIV-positive but is taking his medication on the prescribed schedule and if his viral load has declined to the point where it is undetectable, then you are completely safe. Undetectable = untransmittable. U=U | United States | Prevention Access Campaign