What are my odds of contracting HIV from 1 unprotected heterosexual?
According to the CDC, the odds of getting HIV from one act of unprotected insertive vaginal sex with an HIV-positive person are somewhat less than 1 in 1000, or .04% to be exact. Yes, those are the real odds. HIV is actually much less contagious than most people think it is. In the United States, less than 1% of the population has HIV. So your odds of getting HIV from one act of unprotected heterosexual sex with a random partner are even smaller, on the order of .0004%. What you really should be worried about instead of HIV are the other STDs you could possibly have gotten. You might have gotten herpes, HPV, chlamydia, gonorrhea, syphilis, or viral hepatitis. Those are all far more common and far more contagious than HIV. And some of them are pretty nasty. I strongly suggest you stop worrying about HIV and go get yourself tested for those other diseases. And then stop at a drugstore on the way home and pick up a pack of condoms.