Oral

Hello -
In the past I have been very careful about asking all my partners their HIV status (all have said they're negative and never have given me an evasive or sketchy answer) - last night was no exception.  I recieved unprotected oral sex from a man.  I found out that a half hour before he was with me, he was with another guy that also ejaculated in his mouth.  Both say they're HIV negative.  With respect to HIV risk, where do I fall - I couldn't sleep last night - so I'm looking for some guidance.  I'm now an MS2 - so I've been reading about proteolytic enzymes in the mouth that may or may not denature HIV, etc -- but I'm trying to keep a level head about this.  Thanks! -DM

[H. Hunter Handsfield, M.D.]

Welcome back to the forum.  Last September, we discussed the low risks of HIV form oral sex in quite some detail.  In addition, the question immediately before this one also was on the HIV risks associated with oral sex.  Take a look, and also at the other websites mentioned in that reply:  http://www.medhelp.org/posts/HIV-Prevention/safety-of-oral-sex/show/1439594

Your current concern is whether there might be risk not because your partner had HIV (apparently he does not), but whether people's body orifices can serve as reservoirs of previous partners' genital secretions and therefore a source of transmission. This actually comes up most often when people are concerned that their female partners may have previous partners' semen in their vaginas.

There are no data to answer this question, but logically there must be zero risk or very close to it, especially if more than a few minutes have passed since the partner's previous exposure.  By 30 minutes, at least 3 factors would have greatly reduced whatever small risks might have been present if there had been an immediate partner change:  1) there woulnd't be much ejaculate remaining -- it would have been mostly swallowed or expectorated; 2) dilution of whatever remained with the person's own oral secretions; and 3) degradation of HIV by saliva, which naturally inhibits the virus (as you already know).

To that reasoning, I would add that oral sex among MSM is very common in group-sex (or semi-group) settings, such as bath houses and saunas; and that rapidly sequential exposures of this sort must be quite common; and still the overall risk of HIV acquisition for the penile partner in fellatio averages somewhere around 1 in 20,000 (maybe zero, according to some experts).  So if such transmission every occurs, it must be exceedingly rare.

For all those reasons, my judgment (I stress judgment, not rigorous science by any means) is that HIV is rarely if ever transmitted in this fashion and I consider your risk of HIV to be zero, for all practical purposes, from this event.

Good luck in your medical training and future professional success.  Stay safe--  HHH, MD