Genital to mouth to genital transmission - a realistic possibility?

[gay_male_hpv]

I am a gay man with warts around my anus. I do not have any on the front.

Your colleague Dr Jose said that the chances of passing HPV orally are around 5%. I know the chances of developing warts in the mouth are slim but I think he was talking about transmission of the virus (whether symptoms occur or not.)

I have a few questions:

Does the length and nature of exposure have an impact on whether the virus is passed on? I recently received oral from a guy for about 30 seconds and my penis went right to the back of his mouth. He was quite rough and there would have been a lot of friction between my penis and the back of his throat. What would you say are the chances of infection? Surely it would be a lot higher than five per cent in this instance?

I also want to know what the chances of oral to genital infection are. If someone has asymptomatic HPV in their mouth, can they still pass it on via oral sex? Dr Jose states that the chances of infection are ‘around 5% for all types of orogenital transmission, similar both ways.’ Is this correct? (http://www.medhelp.org/posts/STDs---International/Oral-HPV/show/1248535)

In a previous question, you said there was no need to tell oral sex partners about HPV, due to the fact that oral is low risk and most oral infections that do occur are asymptomatic. I can understand the logic in that. However, if it is possible for me to infect someone orally and for them to then infect someone else, should I still tell them? Should I warn oral sex partners that this could happen or are the chances so slim that it is not worth mentioning?


One more quick question. I have read that the average person clears the virus within six months and 90% clear it within two years. How much is this dependant on a healthy immune system? I don’t have a great diet if I’m honest. I probably don’t get enough vitamins, etc. Does this mean my immune system might be slightly weaker than most and, therefore, the virus will take longer to clear?

[Edward W Hook, MD]

Welcome back to the Forum.  In preparing to answer your question I reviewed the thread on the International STD Forum you referred to as well as your earlier interaction with Dr. Handsfield.  I agree with what you've been told and read thus far with a minor discrepancy.  As both HHH and Dr. Jose have said, the issue of oral HPV and its transmissibility, like estimation of risk for oral cancer from oral HPV infection is, at present, unclear and the topic of active research.  I think the estimate that HPV is transmitted orally being around 5% is a bit high but would not venture another estimate (Perhaps sadly it is a fact that it is easier to publish results with higher estimates than lower ones, in part because editors find such data more attention attracting which will in my mind, not the same as "newsworthy"   Higher estimates thus tend to be published more easily).  Whether it is 5% of 0.5% is, in some ways almost irrelevant- the fact is it happens but not most of the time, that lots of people have oral sex and that while the statistical estimates of risk for transmission and/or later consequences are still being refined, transmission clearly occurs from time to time and cancers from such transmission, particularly in the absence of other risk factors such as smoking (the single largest risk factor for oral cancers) is quite low.  Further, I must also point out that my own appraisal of risk for oral HPV is also probably colored by what we are sure of which is that ano-genital HPV is both common an clearly leads to adverse consequences if undetected and untreated than oral infection, thus in a relative sense oral infections are not a problem which approaches those of ano-genital infections as a potential health problem.  Not trying to be cavalier here but these are the facts.  Is there risk- yes.  Is it large, probably not.  With this as background, let me address your questions:

1.  Duration of exposure almost certainly does affect risk with longer exposures increasing risk.  How much is hard to say, in part because such exposures are not accurately reported/estimated.  Friction has been shown in experimental studies with animals to increase the likelihood of transmission of HPV.

2.  I addressed this above.  I think that 5% may be a bit too high but how much too high is hard to say.

3.  I agree with Dr. Hands field’s earlier comment that disclosure of the possibility of HPV is a personal choice.  Admittedly this is colored in part by the fact that virtually all sexually active persons will get HPV and thus, in the absence of known infection (which you have, rectally) I would not feel the absolute need to disclose.  On the other hand a frank and open conversation with potential partners is always a good idea although I suspect you will find that most persons are neither as well informed or as thoughtful about this as you are.

4.  The role of nutrition an vitamins in maintaining health is difficult to state. I doubt that your diet is having an averse effect on your clearance of HPV unless you are frankly malnourished.  The immune system has great resilience and other things are more likely to indicate viral deficits than problems clearing HPV.

I hope these comments are helpful.  EWH

[Edward W Hook, MD]

This could go on an on.  You asked for my advice, then an explanation, both of which I provided.  This Forum is not for debate but for provision of informed infomation and guiance to clients- I've done my best to do that.  This will be my last answer and the thread will then end and you will need to consider what you wish to do with the information I have provided.

The fact is that with anal sex, what limited data are available AGAIN indicate that the receptive partner is at greater risk for infection than the insertive partner.

Indeed, as I have indicated before, while theoretically HPV can be transmitted by "touching" (whatever that means), the likelyhood of this happening is low.

This ends this thread.  EWH

[gay_male_hpv]

Couldn't the same be said of anal sex though? The penis is inserted and then withdrawn. Yet this is considered high risk.

I understand that HPV can be passed on by genital touching (i.e. someone rubbing their penis against someone else's penis.) Is this also very low risk then?

[Edward W Hook, MD]

Think anatomically.  With oral to genital transmission the source of infection (a penis) is inserted, then removed.  Innoculation occurs only when the penis is present, once the penis is out is drys off and secretions are removed. On the other hand, with genital to oral transmission inoculation occurs an remains behind in a warm, moist enviroment conducive to infection.  For the same reasons male to female (vaginal) transmission of gonorrhea is twice as "efficient" as female to male (penis) transmission.  EWH

[gay_male_hpv]

Thanks. But I'm not sure how biology would suggest that. I know you know what you're talking about but could you possibly explain why you think oral to genital would be less likely? Since the HPV virus prefers to live on the genitals, I would have thought that would make it more likely... I'm not saying you're wrong, I just wanted to understand it a bit better.

[Edward W Hook, MD]

There are no good data to address your question (the studies would be very hard to do).  Biologically, I would anticipate that oral to genital transmission is less likely/efficient than genital to oral.  I suspect if happens but again, I think the 5% estimate is too high and perhaps far too high. EWH

[gay_male_hpv]

Thank you very much for your quick reply. There is just one point I still need addressing:

Would you say there is a chance of oral to genital transmission? Doctor Handsfield told me that oral infections are virtually never passed on any further but, according to Doctor Jose, there a definite chance it can be passed from the mouth to the genitals. They are both saying very different things.

I can understand why it is rare for HPV to be passed from the genitals to the mouth as the virus does not like the tissue there. But surely the virus would travel more easily from mouth to genitals as it is leaving an area it doesn’t like for an area it is better suited to. Do you know why Doctor Handsfield thinks that mouth to genital transmission rarely occurs? I am interested to know his reasoning for this.