I'm a gay male virgin who recently engaged in foreplay with another male of dubious status under the (mis)perception that this was entirely risk free. Potential exposure to HPV continues to aggrieve me as a result of said individual masturbating themselves before me. Naively, I did not expect him to do this and so had him apply hand sanitizer (70% ethanol) and incidentally he also touched my shirt before my genitals. To my dismay I've since learned that hand sanitizer is useless against HPV. That leaves me reliant upon the microbiological dilution effect articulated by Dr Hook:

"With each intervening possible point of transfer (i.e. from genital to hand then hand to genital equaling two rather than one transfer opportunities) the risk for infection goes down about 100-fold."

1. Discounting the hand sanitizer, do I correctly understand that the risk of infection was diminished circa 99.99% by the simple fact of this individual touching their penis and then my clothes, as compared to direct contact of genitals? If touch is so effective at reducing infectivity, why is there such emphasis on handwashing for hygiene as opposed to just wiping our hands with tissues for example? Is this a unique property of STI pathogens?

2) I notice in some posts that Dr Handsfield speculates that hand-genital transmission of HPV is probably more likely where genital secretions are used for lubrication. I thought HPV is transmitted through skin, not through secretions. Please can you explain this?

I'll start by first saying there was no measurable risk of HPV from the events described:  you needn't be at all worried. I'll expand on this reassurance below.

However, you also need to be aware that aside from lifelong celibacy, there is no 100% protection against HPV. You should assume and accept that you will be infected someday. Fortunately, most infections are harmless; and you can prevent almost all potentially harmful outcomes by being immunized. The HPV vaccine prevents 9 of the 100+ sexually transmitted types of HPV, and these 9 types cause about 90% of all genital, anal or oral warts and cancers caused by HPV. This vaccine is among the most effective of all vaccines ever developed by medical science. (You'll continue to be infected by several of the other 90+ HPV types, but probably you'll never know it. Having genital or anal HPV is a normal, expected, unavoidable consequence of being sexual. Now to your specific questions:

HPV is rarely if ever transmitted by hand-genital contact:  you were at little or no risk on account of your partner masturbating himself before his hands contacted you. I'm not aware of any data on the "microbiological dilution" you mention, and I'm pretty sure Dr. Hook did not imply that there are data to support a hundred fold reduction in transmission risk on that account. More likely that was just a rough guesstimate. In any case, that figure shows he agrees there is little or no risk at all of HPV (or any other STI) from hand-genital contact, even if genital fluids are used for lubrication.

1. The hand sanitizer probably made no difference in your risk of acquiring HPV. In the event of a future exposure to a partner's genital fluids, a gentle soap and water wash probably would be more effective in preventing HPV and perhaps less irritating. I am unaware of any "emphasis on hand washing" to prevent transmission of HPV or any other STI. That said, soap and water are highly active against non-STI viruses and bacteria and might have modest prevention benefit against some STIs transmitted skin to skin (like herpes and syphilis in addition to HPV). (I wonder if you're conflating all the recent advice about preventing COVID, colds, influenza, etc with advice about STI prevention.)

2) You have misunderstood something. It is true that HPV is transmitted predominantly (maybe exclusively) by skin-to-skin contact, and I have never said that hand-genital transmission is a regular occurrence. In theory, could this happen? Probably yes. But I have never seen a patient with genital HPV, or any other STI, whose only potential exposure was masturbation by a partner. So if this occurs, it is too rare to worry about. As already implied, if you would feel better by washing gently after such an event, feel free -- but don't freak out if you have had such contact and don't have easy access to clean-up. Showering a couple hours later probably would be equally effective.

I'll conclude by reiterating the most important part of my advice:  get vaccinated against HPV before you have any further sexual contact with anyone. Three vaccine doses is routine (i.e. repeat doses one and 6 months after the first), but  protection is nearly complete within a couple weeks of the second dose. So you would need to abstain only for about 6 weeks in order to be protected for life.

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD

Good day Dr Handsfield,

Thanks for your considered reply.

I'm fully vaccinated with Gardasil 9 but conscious that it doesn't protect against all carcinogenic strains. I'm also aware that new ones continue to be discovered and the virus mutates. In Scotland anal pap smears are unavailable even to men deemed at high risk (participants in anal sex). DNA tests aren't comprehensive and don't catch the virus if it's incubating, which it can do for decades. Ergo it's very much 'wait to see if it comes back to bite me'. Nothing breeds anxiety like such uncertainty.

Here's the post by your distinguished colleague re. microbiological dilution:

https://medhelp.org/posts/STDs/hpv-transmission/show/2150527

Dr Hook repeats this on this forum in question #4417, "STD via hands". It seems an oddly specific contention sans data?

There were no genital fluids involved in my encounter but the reason I'm kicking myself is in accord with your advice, i.e. I've since read that soap (specifically SLS/SDS) inactivates HPV. Is this true? Your reply suggests some uncertainty. Would showering within two hours be as good as having had him handwashed with soap before contact? I've read that HPV exhibits 'extended kinetics'; that infection takes 12-24 hours. Can you comment on that?

Would you advise use of gloves?

I interpret Dr. Hook's comments in that old post (on our previous forum) as I described them above:  an approximation intended to reassure the questioner, not a citation of scientific data. We routinely advise forum users -- especially those with evident anxiety or heightened concern -- to be careful in applying previous answers to their particular situations. Different contexts can result in different wording or emphasis; don't split hairs over minor differences in wording. In addition, you have focused on only part of Dr. Hook's reply, missing what was arguably his most important advice:  "...we really do not see concerns about HPV transmission as being worthy of concern anyway, given that virtually all sexually active persons will have HPV at some point...."  (And you far less likely than most persons, given your vaccination!)

To my knowledge, all soaps indeed inactivate HPV. And no, I would not recommend gloves (or condoms) for hand-genital sexual exposures.

In summary, these comments do not change my opinions or advice, and I see no reason for you to be "kicking [your]self" over the sexual exposure you have described. 

Thanks for your kind advice Dr Handsfield.

What chills me about HPV is that it is to some extent avoidable e.g. through abstention, a partner who's a true virgin, or perhaps one of the pan-protective/L2 vaccines in the not-too distant future. I eschew anything which might engender other cancers (drinking, smoking) so my approach is the same with respect to sex, or lack of it. It saddens me that these things even exist.

I tried to learn what I could from these forums and thought I'd found a way to safely explore my sexuality through hand-genital contact as it was couched in terms like zero risk, completely safe sex etc. but with hindsight felt I ran afoul of the theoretical/low risk. Being hit by a meteorite is a theoretical risk but the fact is I wouldn't have engaged in any casual encounter if I'd thought there was any STI risk (I was naive). That's why I'm beating myself up for not taking the proper precautions, particularly when they amount to something as trivial as the choice of soap over hand sanitizer. Had I done that HPV would be out of my mind.

I read in another answer that you don't recommend permanent mutual monogamy. Please can I ask why?

I am reassured by your responses and grateful for the time you've taken to share them. I wish you well and will try my best to move on.

Why not permanent mutual monogamy? First, arguably it's not inherent in human nature and evolutionary development, and certainly it's not a rational or practical lifestyle choice for the vast majority of people. I also don't recommend people avoid travel in automobiles, even if that statistically would be a good investment in longer survival. Second, in essence that choice means someone is excluding a high proportion of all potential committed sex partners -- in American or Western European societies, for example, up to 90% of all potential partners -- lower percentages in other societies, but probably almost always over 50%). Avoiding HPV or other STIs doesn't seem remotely to be worth such a sacrifice. Third, it's a forlorn approach doomed to failure in most people, both because of natural human biology and psychology, and because people so often would give inaccurate information about past sexual experiences, sometimes intentionally, sometimes unknowingly (consider repressed recall of childhood sexual abuse or exposures when under the influence of alcohol or drugs), and sometimes because people have varying perceptions of what constitutes "sex". All in all, of course this almost never can work and strikes me as a nonsensical approach to romance sexual fulfillment. Even if all STIs were as deadly as HIV, I would not propose permanent lifelong monogamy as rational for most people.

That concludes this thread. I hope the discussion has been helpful to you. Best wishes.