[Question #10398] HIV testing and fears

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23 months ago
Dear Dr. I am a hetrosexual 40 year old male who had an encounter with a female CSW (she was a Brazilian) based in UK. The encounter consisted of unprotected oral - and vaginal sex which I THINK was protected but do not remember if it was due to intoxication! I have suffered with crippling anxiety over HIV ever since so wanted to ask for your opinion. I have had the following tests done so far:
HIV RNAPCR test for HIV 1. 12 day post exposure. NEGATIVE
HIV rapid alere finger prick combo/duo test 4th gen. 15, 21 and 28 days post exposure. NEGATIVE  
I have taken all other tests for Chlamydia, Gonhorea, syphilis, hepitis B and hepitis C. All negative and I have accepted the results but it is the HIV test types and window periods that confuse me. Dr HHH says 28 days for the duo whilst Dr Hook says 6 weeks. And official government advice suggests 12 weeks which I dont want to do if unesessary. I have a wife and am scared of unprotected sex as we want to try for a baby oneday
What I want to ask is
1. Please can you elaborate on whether I need anymore testing or whether my results based on the tests specified are conclusive?
2. If conclusive does this rule out both HIV1 and 2?
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Edward W. Hook M.D.
23 months ago
Welcome to the Forum and thanks for your questions. I can understand how interpreting HIV test results can be confusing- they have changed over time and there are several different types of tests.  I'll be glad to comment:

1.  Background.  Even if unprotected, the exposure you describe was rather low risk.  There has never been a case of HIV proven to have been acquired due to receipt of oral sex and even in the unlikely event that your partner had HIV (most CSWs do not have HIV, it's bad for business), the likelihood of acquiring HIV from a single unprotected vaginal sex act with an untreated, infected person is less than 1 infection per 1000 encounters.

2.  You can be confident that you did not acquire HIV from the exposure you describe  Your results are conclusive.  FYI, Dr. Handsfield and I provide the same information on testing.  We agree that when used alone, DUO combination HIV antigen/antibody tests are more than 99% conclusive at 4 weeks and agree with CDC recommendations that results of these tests are 100% conclusive at 6 weeks.  When an HIV PCR Test is negative at any time more than 11 days following an exposure, if confirmed by a negative DUO test at 4 weeks, this combination of results is also conclusively negative (this is your situation) - you can be confident that you do not have HIV.

3.  You can believe your test results for gonorrhea, chlamydia, syphilis and hepatitis- you do not have these infections and do not need more testing.

4.  There are several different types of PCR tests for HIV.  Some test only for HIV-1 while others test for both HIV1 and HIV-2.  If your PCR test tested for both HIV-1 and HIV-2, your results are conclusive.  If the PCR test was only for HIV-1, you should repeat your DUO test at 6 weeks to be entirely confident that you did not get HIV-2 although it is most unlikely that you did.

I hope this information is helpful.  If I were you, I would not test further and would be confident that I did not get HIV from the encounter you have described.  EWH

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23 months ago
Hi Dr. Thank you for your reply and detailed explanations which are appreciated. I would have thought the HIV duo tests already taken (3 times) would collectively rule out HIV 2? What are the chances/probability I acquired HIV '2' based on the scenario and test results to date? I do not want to retest at 6 weeks if not recommended or necessary. I was ready to move on but now worried again. My instincts tell me I am sure I used a condom for the vaginal sex (as it is in my day to day nature to do so) - it is only my distorted memory of the event which makes me think the worst. I look forward to your reply. Thanks
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Edward W. Hook M.D.
23 months ago
HIV-2 is very, very rare among persons with HIV and there is some controversy regarding when results are conclusive, in part because HIV-2 is so very rare.   Personally, I would consider your results entirely conclusive and would not bother with further testing.  To put a number on it, the chance that you have HIV is virtually zero.  

Please don't worry.  EWH
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