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Transmission Risk and DNA PCR Reliability - PLEASE RESPOND THIS TIME!

Jul 19, 2011

Dear Dr. Bob,

First of all, thank you so much for what you do; it is truly inspiring. I wonder if you might answer a few questions I have, because I have not been able to find specific answers after hours and hours of scanning through 'the body' archives, and am more than willing to donate to your noble cause. I suppose it would be more helpful if I explain my situation first. I performed oral sex on a man on May 6, and he informed me the next day that he is HIV +. Now, he says he has a 0 viral load, there was NO ejaculation involved, and my gums werent bleeding during the act (I hadnt brushed since the morning, and this was late at night). However, I am very concerned because I do have gum disease/gingivitis, and considering I had to have surgery on it last year and still have puffy gums that often bleed when I brush, Id say its pretty serious. I also am apparently an idiot and did not rinse with mouthwash after the act.

How much does the gum disease factor elevate my risk? I know the ratio of transmission for oral sex per encounter is something like 1 in 10,000, but is this number increased dramatically if gum disease is involved? If your gums arent bleeding during oral sex and there are no cuts or anything, how/why is it still so risky?

Now for the second part: I took a qualitative HIV DNA PCR test 19 days after the possible exposure at a Labcorp facility and it came back negative (undetected). I registered for it anonymously through a third-party website who informed me that the specific DNA PCR test they use is the most sensitive one on the market and is considered definitive after 14 days. I know the topic of PCR window period is subject to dispute, but from what Ive read the physicians who do claim DNA PCR tests can be definitive earlier all say 28 days, not 14. Ive found nothing to corroborate the claim of the testing service I used. I have read that DNA PCR tests CAN detect HIV at 2 or 3 weeks out, but about 10% of people dont develop detectable levels of virus in the blood until about a month out. Is this true; do most people develop enough virus in the blood for detection by DNA PCR by 2 weeks out? Have you ever heard of anyone considering a DNA PCR test at 19 days definitive or even reliable? Have you ever heard of anyone getting a negative DNA PCR test and later being confirmed positive through an antibody test? In short, should I be worried about a false negative?

Sorry for all of the different questions, but I think you can probably answer them all with a few dashes of your genius for comforting people with valid information! I hope you respond this time and would very much appreciate some clarifying information because even this long afterwards my stress levels are still going berserk!


Response from Dr. Frascino

Hello, BG.

Oral sex carries only a very low HIV-acquisition risk. Gum disease/gingivitis can increase the transmission risk. How much would depend on the severity of the gum disease. That your partner was apparently on effective antiretroviral therapy, which drove his HIV viral load to undetectable levels, and that there was no ejaculation would significantly decrease your HIV-acquisition risk. Overall your HIV-acquisition risk remains very, very low.

HIV DNA PCR qualitative tests are not FDA approved for routine HIV screening. Consequently there are no reliability statistics or published-guideline recommendations that would answer your question about the definitive reliability of this test at day 14, 19, 28 or any other time. I would suggest you follow the current guidelines for HIV-diagnostic testing. The gold standard remains an HIV-antibody test taken outside the HIV seroconversion window period. I'll try to address some of the confusion about HIV-diagnostic testing in an upcoming blog.

Thanks for your support of The Robert James Frascino AIDS Foundation ( It's very much appreciated. In return I'm sending my good-luck karma that your conclusive HIV test remains negative.

Good luck. Be well.

Dr. Bob

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