I am 22 year old gay man. About a year ago, I had unprotected anal (receptive) sex with a man I now have found out to be HIV+. I am not sure whether he was HIV+ when we had sex. Assuming he was, how at risk am I for being HIV+? He did not ejaculate inside of me, and the sex lasted for less than five minutes. In the past year I have not exhibited any symptoms of HIV. Needless to say I'm regretful and very scared, and intend to be tested soon. But in the meantime, what are the statistics?
The CDC's estimated per-act statistical risk of acquiring HIV from unprotected receptive anal sex with a partner confirmed to be HIV infected is 50 per 10,000 exposures. Please note these are only statistical estimates and there are many factors involved in HIV transmission, both viral (viral strain, viral load, etc.) and host (immune integrity, concurrent infections, local trauma, etc.).
I agree with your plan to get HIV tested without delay. Also, it is worth noting that your choice to have unprotected sex last year is the real concern. You're only freaking out now because you recently learned your top gun was positively charged. Even if you didn't find out about his HIV serostatus, your risk would still be the same! It's also worth noting that 20% of the over 1,000,000 HIV-positive Americans have absolutely no idea they are infected with the virus. We must assume all our bedmates could be HIV infected and take all the necessary precautions to prevent transmission of the virus. Had you used a latex condom last year and then subsequently learned your buddy was virally enhanced, you wouldn't be in your present predicament. I'm hopeful this entire anxiety-provoking experience will teach you never to put yourself at risk again.