risk of hiv infection

To whom it may concern, on 06/04/09, i had intercourse with a prostitute.  She put the condom on my penis and began to perform oral sex.  Shortly after, we had intercourse for approximately three minutes.  I released inside of her and i came.  When i pulled out, i realized that the condom had ripped from the top of the condom.  She reported that she has no STD.  Weeks later, i found out that the person that i was with is a professional transexual prostitute and she had a sex change.  We did not have anal sex.  The next day 06/05/09 i immediatley went to the hospital for a check up.  My test came back negative for std"s.  Is my risk level high.  Does this person have vaginal fluids.  What do you recommend because ive been so scared.  Im scheduled to take a PCR test.

[Edward W Hook, MD]

You have posted on the wrong forum. I will briefly answer your question but if you have additional questions any further questions, they must be on the HIV forum.  Sorry, those are the rules.

The risk associated with this exposure, despite the fact that your partner was high risk, is rather low.  Chances are that your partner was not HIV infected.  Even if she was, your risk for HIV is no greater than 1 in 100 and probably far lower (there are no average figures for HIV risk related to sex with a person who has undergone sex change surgery).  However, I can understand however that you would like to get tested.  To get an HIV PCR at this time will give you no useful information.  Instead, I woud suggest you get a dual, antigen/antibody test at 4-6 weeks following exposure with a follow-up test at about 8 weeks  Your 4 week result will identify over 90% of infections acquired 4 weeks earlier while the 8 week test will give you results that you can be completely comfortable with.  

I hope these comments help. Take care. EWH