HIV and Oral Sex Research

Hi Dr.  Hansfield and Dr. Hook,

First I want to thank you for this website...it has been extremely helpful.  I gave unprotected oral sex to a male I was dating about two months ago, and afterwards I was extremely anxious.  However, this sight helped to reduce my anxiety since it helps me to have actual statistics and numbers rather than just statements that risks are "high" or "low."  However, because I still tend to be on the anxious side, my question is what was unconvincing to both of you about the current research on the topic?  I read about one article that found that something like 8 out of 120 individuals were infected with HIV solely through oral sex, which is a lot different than 1 out of 10,000.  I realize research can sometimes be misleading, so to help calm my lasting anxieties, can you explain briefly why you weren't convinced that the results were accurate?

Thank you so much for your time and your help....it's appreciated more than you know.  

[H. Hunter Handsfield, M.D.]

Welcome to the forum.  I'll try to help.

Be careful when reading and interpreting statistics.  In this case, you are comparing entirely different kinds of numbers.  One is the proporation of people with HIV who caught it by various kinds of exposure; the other is the chance of catching HIV from any particular exposure.  That 7% of people with HIV apparently caught it by oral sex (8/120 = 7%) is entirely compatible with a risk of 1 in 10,000 for each oral sex exposure with an infected person.  The transmission risk for vaginal sex is around 1 in 1,000 (10 times riskier than oral), and for anal sex it's around 1 in 200-500 (different for the receptive versus insertive partner).  These numbers are entirely consistent with a proportion of somewhere around 7% of infections due to oral sex and the rest (93%) from vaginal or anal.

And you are exactly right that such research can be misleading.  All these data depend on people telling the researcher when and how they think they were infected, and often they are wrong.  Almost all people with HIV have had multiple exposures and can only make educated guesses about the source.  As one sort of example, consider the person who has only oral sex with casual partners and assumes that's where he was infected, when in fact he is unaware that his regular partner -- with whom he has anal sex -- has HIV and is the actual source of infection.

In other words, all these data are imprecise.  Look at them as pretty good educated guesses, but not much more than that.

Regards--  HHH, MD

[joggen]

The study you referred to was published as an abstract of a poster. These are not subject to the peer review process, where other scientists scrutinize the methodology and results before something is published as scientific 'truth'. I could not find a corresponding journal article for this.

Further, initially 20 men in the study were suspected of having contracted HIV by oral sex, and they had to disregard much of that group upon further examination because other routes of transmission were later 'discovered'. How the remaining 8 were classified as 'likely' cases isn't explained.

And studies in serodiscordant couple have not shown transmission through oral sex, even those in which more than 19,000 acts were performed.

http://gateway.nlm.nih.gov/MeetingAbstracts/ma?f=102243351.html

[verypanic]

Hi, Dr. HHH,

Pls. be so kind to have a look at the following discussion between Teak and another member, which is really confusing.

http://www.medhelp.org/posts/HIV-Prevention/tested-positive/show/1001898

Then does this mean the risk is really existing and no more just a theory.

Really appreciate it, Dr.

[H. Hunter Handsfield, M.D.]

I haven't read that thread and do not intend to.  But oral-genital transmission of HIV has never been "just a theory".  Although some experts believe mouth-to-penile transmission never occurs, most agree it happens but very rarely.  It is so rare that 99% of the people who worry about it should just get a life and forget about it.

That's all for this thread.