Risk reduction statistics for herpes: effectiveness of condom use?

[JohnB23]

What is the latest/best estimate of condom effectiveness in reducing risk of transmission?

 

I have seen estimates of condom effectiveness in preventing HSV2 transmission range from 30% (meta study of other studies, but confounding factors abound) to 90% (2001 study, measuring transfer from men to women), to very significant risk reduction with a "confidence interval consistent with complete protection" (May 1, 2013 NIH study "Case-crossover analysis of condom use and HSV-2 acquisition"). Some people say 50%, which is from yet another study.

 

The most recent study I could find, the 2013 case-crossover study seems the most relevant, but the data is risk "per act" not "per period of time" and so is harder translate into a risk reduction estimate for an average couple over time vs. a baseline risk level (any statistics experts please feel free to chime in). The 2013 study also wasn't clear about serodiscordant couples vs. single individuals, as the analysis showed different effects, for unknown reasons.

 

Is anyone up to date on the research around this issue, and/or willing to offer an opinion?

 

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All studies are available via PubMed

 

From the May 2013 Case-crossover study:

 

"This approach detected a 3.6% increase in the odds of HSV-2 acquisition with each unprotected act (odds ratio (OR)=1.036; 95% confidence interval (CI): 1.021, 1.052), but no increase in the odds of acquisition associated with protected acts (OR=1.008; 95% CI: 0.987, 1.030)"

 

"In either analytical approach, the confidence interval surrounding the OR for the risk of acquisition with protected acts included 1.0; as an OR of 1.0 corresponds to 100% efficacy, these findings are consistent with but do not demonstrate complete protection."

[HerryTheHerp]

Offer an opinion? Well, in my case the little rubber shields were about as effective at stopping herpes as throwing bb's at a tennis net.

 

There are so many factors that go into the transmission risk that it's very difficult to calculate effectiveness. Folks are more contagious in their first year and shed far more frequently. Is the person on suppressive therapy? Are you taking transmission from a male to female, or female to male? Is it a female condom (more effective because more coverage.) Plus, does the person's body get it under control after that? How soon after a prodome or an outbreak does the person have sex? Is the person's partner "well endowed" thus causing micro tears within the vagina that can facilitate easier transmission. Is it rough sex? Prolonged sex? Did the couple shower before and after?

 

Overall, they help considerably, but there's a lot of guys here, myself included who wrapped it and tapped it, and well, might as well have been wearing a cheesecloth.

[WCSDancer2010]

I can't add anything more to that. Scientific studies are most effective when you can have consistent variables across the board. As Herry pointed out, there are too many variables to take any one study to the bank.

 

Yes, condoms reduce the risk. And any reduction is better than nothing....besides the fact that you should wrap it up to protect from other STD's and unwanted pregnancy. But I wouldn't rely on condoms to protect you completely. I'd rely more on anti-virals and being uber-careful during anything that *might* be an OB.

[JohnB23]

Thanks so much for the comments. The older studies are hard to interpret broadly because they were not designed to test condoms and, as you note, don't have consistent populations or variables (and rely on less-reliable self-reported use statistics, since condom use vs. placebo cannot be ethically studied).

 

The 2013 case-crossover study is interesting, however, because it attempts to correct for these problems (i.e. by measuring individuals with outcomes against themselves in an earlier measurement period, so behavior differences and reporting bias should be minimal) . . . it is a statistical strength of the study, and seems to offer the best analytical evidence in support of the effectiveness of condoms in reducing transmission risk incurred via incremental acts by a given individual . . . I just see a lot of people saying "30%" or "50%" when really it is "unknown, each situation is different, better than nothing", but one could also say that the "recent 2013 case-crossover study better controls for confounding factors than earlier studies and suggests 80-90% reduced risk for each protected vs. unprotected act for individuals included in that analysis".

 

For some people, condoms might be 100% effective. For others, the specifics of their condition and behavior might make it 30%, or even less. But the "on average" data is what helps people form an opinion about what range of protection is most likely - and this is the key of the case-crossover study: the protective effect is vs. the risk these individuals were incurring with unprotected acts, so it tells more about the reduction in risk per individual, rather than less reliable conclusions about the absolute level of risk (both of which are helpful to know).

 

 

[WCSDancer2010]

Exactly - if the herpes is in a guy, on his penis near the head, a condom would be near 100% effective... if it was at the base of the penis, probably 50% at best.... likely more like 30%...

 

I think if you tell someone that a condom reduces the risk by 50%, they at least know that in general it's worth wrapping it up BUT it's not guaranteed enough to get lazy about the other precautions. It's the best we can do with a very imperfect situation.

[whatsallthehubbub]

My opinion is: if it reduces transmission of any std by even a fraction of a percent its worth using clean with casual sex.. h+ with a h- partner (unless the h- partner says no ). I cant see any case where wearing a condom is a bad idea. As it relates to herpes and its transmission.. id go with the lowest number... with the understanding of how they generate those percentages.

[JohnB23]

Thanks for the comments. I agree it is better to be conservative in estimating the risk (ie nothing is 100%). Although part of the issue here is individual specific (ie male/female sheds virus from area just beyond reach of condom), a lot of the data suggests condoms are highly effective on average anyway (ie case-crossover study).

 

While I think the site of ob, if it can be determined should be considered in risk reduction strategies, other factors appear very significant also (or even more significant in driving the risk data).

 

Most data I have seen suggests that the virus sheds most readily from the thinnest skin / mucus membrane during asymptomatic shedding (and is much less able to shed from thicker skin further away from these sensitive areas) - and that the highest risk of transfer is skin-to-skin contact of these most sensitive thinnest-skin areas (which are also more prone to micro abrasion) during intimacy.

 

So I see no reason why, even if you get ob's in an area outside condom coverage, that condoms would not STILL be highly effective (ie they stop mucus membrane / mucus membrane and thinnest skin / skin contact - and cover the area with the greatest risk of asymptomatic shedding - and likely greatest risk of vulnerability, going the other way - on a man). I think the case-crossover statistics suggest strongly that the protective effect per act, on average, is much better than 50%, although 70-90% on average could be noted to be based on a study averages in which some outliers likely existed, for whom it might be more or less effective (a 60% to 100% range would give a greater confidence interval, but in no way would a simplistic "50%" reflect anything close to what the study indicated - which was a confidence interval consistent with, but not demonstrative of, a complete protection effect).

 

It seems to me to be theoretically a bit like kissing someone who gets cold sores sometimes - less risky when no sore is present, greatest risk is oral mucus membrane direct contact with friction/micro abrasion, can imagine that use of a dental dam would probably be highly protective per act of kissing (but not 100% - because the virus could shed from an area not covered, and also possibly infect abraded skin anywhere on the other person's face if contact occurred there, but the most vulnerable mucus membrane in the mouth would be highly protected) . . . it seems safe to assume that a dental dam would likely be really effective (if cumbersome and impractical), and the risk reduction significant, if it was used to protect against possible asymptomatic shedding (allowing for the fact that we all know that HSV-1 sheds less than HSV-2 to begin with) . . . no one actually does this, because HSV-1 isn't a big deal culturally, but the mechanism of transmission is very similar for the nearly identical viruses . . . so the conclusions drawn from the case-crossover study might likely apply to barrier protection risk reduction for oral HSV-1 as well (and this would seem reasonable, given what we know about the viruses) . . I would bet that a similar study on HSV-1 and dental dams might lead to similar case-crossover study conclusions about the effectiveness of dental dams being consistent with total protection, but not demonstrative of it (if enough people that actually use them could be enrolled in a study) . . .

[JohnB23]

It's worth adding that the case-crossover study results were based on individuals, and reported sex acts (either protected or unprotected), not established h+ / h- couples.

 

The data for couples that was analyzed in the study did not indicate any firm conclusions - in part this was speculated to possibly be due to smaller sample size, and/or because most couples didn't use condoms consistently, possibly reserving condom use for higher risk periods of time or higher-risk acts. A number of other factors may have affected the study, including couples behavior being different in other ways from individuals not in committed relationships (or other selection bias / confounding factors).

[WCSDancer2010]

and cover the area with the greatest risk of asymptomatic shedding

 

The outer lips of the Labia often come in contact with the skin of the male outside the condom area - just ask Herry - he learned that the hard way. Many people have their main OB's on the thighs/buttocks/scrotum/etc. I personally would assume the lowerst number to be the one I would go by and if it ended up that condoms were more effective, well,... BONUS! BTW, they are now saying HPV can also be passed with a condom on :p

 

The data for couples that was analyzed in the study did not indicate any firm conclusions - in part this was speculated to possibly be due to smaller sample size, and/or because most couples didn't use condoms consistently, possibly reserving condom use for higher risk periods of time or higher-risk acts. A number of other factors may have affected the study, including couples behavior being different in other ways from individuals not in committed relationships (or other selection bias / confounding factors).

 

If the couples didn't use condoms consistently, then IMO the study is not useful. It has to be an all or nothing deal otherwise the data will be skewed :/

[JohnB23]

Thanks for your reply. I think maybe you misunderstood how this study was structured though. This case-crossover study was designed specifically to address the concerns people had with the conflicting implications of earlier studies (30%, 50%, 90%, different data sets and risk characteristics in the populations studied, etc.).

 

We could all go through life taking the lowest number anyone ever found "to be conservative", but really it might be better to say "I don't know, but estimates range from 30-90% depending on the different studies over the years - and the most recent and robust statistical analysis, done in 2013, suggested a number closer to the higher end of that range."

 

As an aside - there is no study in which most people consistently used condoms (because apparently, most people don't) - that is why case-crossover is useful statistically, because it measures the risk per act for individuals (protected vs. unprotected). This is obviously more accurate than broad categories of measurement applied across non-representative sub-populations (ie the problem with previous studies).

 

Also, I think most people know how the virus can be spread by skin/skin contact - what the study suggests is that "areas not covered by a condom" are also by far "not the most likely" route of transmission - indeed, while we all know it's possible, the statistics suggest that it is MUCH less likely that the virus would be transmitted this way compared to an unprotected act (as evidenced by the dramatically increased risk associated with unprotected vs. protected acts).

 

The couples-specific subset of data from previous studies is what is small and inconclusive (for a variety of reasons) - not the overall data set or the conclusions of the 2013 study itself, which is based on all of the other data available from all of the other studies - this study is a meta-analysis, and it includes the "30% study" and all the others in the data-set (whenever enough detail is available - it's worth noting that several of the lead researchers in this 2013 study are the same people who did the 30% study and some of the other studies, this is just a more recent and robust look at the same data in the aggregate).

 

I think the 2013 case-crossover study is the best designed study that has been attempted to date, by the foremost experts in the field, and I think the conclusions are statistically convincing.

 

Perhaps it hasn't received the attention it deserves, but I hope that people will read it and understand how much of a positive impact more widespread and consistent use of condoms would be likely to have in reducing transmission rates of HSV2 (it's important because the statistics show that it's a lot better than just a 30% risk reduction, it's statistically a 70-90% risk reduction per act).

 

I think the study speaks for itself. And it might be worth reading it, even though it's a little bit of work.

 

 

[JohnB23]

A link to the study should anyone wish to read it: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3334342/

[PrimordialOoze]

That's it! No sex for me! It slays me to think that even though I may take every single precaution that I may - just may transmit this. I would not be able to live with myself :/

[WCSDancer2010]

@PrimordialOoze

 

Then don't get in your car either, because no matter how many precautions you take, you MAY kill someone (or die yourself). The risks of dying in a car accident (over here...don't know your numbers in India) are about the same as getting Herpes with "normal" precautions on both sides.

 

Life has risk. We do what we can to protect ourselves and others. Some of us are more responsible than others. Some are more educated about the risks. Some are "better drivers". If you want to LIVE life, you take risks every day for harm to you AND those around you.

 

(((HUGS)))

[Ecureuil08]

Let's just say the first time I had sex with my boyfriend (and second and third and fourth), we used a condom. I still got herpes. Whatchya gonna do? Even if we saran-wrapped both of our lower halves with multiple layers...the chances of transmission are still there. The worst part, is when you don't know you have it. Or your partner doesn't know he has it.

[JohnB23]

I share your concerns about transmission risk . . . but here is something important to consider: the risk reduction from condoms in the 2013 study was very significant (with a 95% confidence interval consistent with, but not demonstrating, a 100% protective effect) . . . in addition, we know that medication is "at least" 48% effective in transmission risk reduction (likely more if you take it every day, but people in the study demonstrating efficacy had mixed compliance, ie forgot to take medication sometimes - and with better compliance it is likely be more effective) . . . what's more, it seems like using both meds and condoms at the same time is highly effective in practice, not just in theory (in the 2004 Valtrex study, only 2/211 couples who took Valtrex AND used condoms "nearly always" showed seroconversion - and zero showed symptomatic infection) . . . 2/211 doesn't prove anything because it is a small sample size and compliance was not precise (usage of condoms and meds was and not 100% in that group of people), but it does suggests that the risk level might be pretty low (2/211 is about a 1.5% acquisition rate on a per year basis - it was an 8 month study). The effect of both taking meds 100% of the time, and using condoms 100% of the time, is likely to result in an even lower average acquisition/seroconversion rate based on the preponderance of the data (If one were to estimate an implied "perfect/high compliance" rate, one might get something more in the range of 0.25% to 1.5% on average overall per year).

 

The Valtrex study FDA presentation slides are linked below (slide 27 and 28 shows the acquisition rates by clinical endpoint - note these particular slides are not segmented by male/female):

 

http://www.fda.gov/ohrms/dockets/ac/03/slides/3950S2_04_FDA-Valtrex.ppt

 

As an aside: although it would be cumbersome, if you did actually wear a fully body latex suit, or some kind of barrier like that just in the "boxer short" area, the risk would likely be very close zero - unless something malfunctioned . . .

 

[JohnB23]

As a further aside: the risk of death in a car accident over your lifetime is similar to the risk of HSV-2 acquisition in one year - on a per-year risk basis, a car accident death is much less likely (apples to apples) . . . but it does highlight how low the risk is in general terms . . .

[JohnB23]

If the risk per year was 1% when taking basic precautions, a couple could be together and have sex 2x per week on average for up to 50 years . . . and even after all those years, it would be more likely than not that they would avoid transmitting the virus . . .

[JohnB23]

Also, if you do the math, the risk of getting HSV-2 from a person who knows they have it and takes all precautions . . . is significantly less than the risk of getting it from a person who hasn't been tested (most people haven't) and who doesn't take full precautions (most people don't) . . . using condoms 100% the time in both scenarios would bring the risk numbers close to parity

 

So unless you are in the habit of requiring an accurate HSV-2 test for every new partner (remember this test is not included in a standard STD screen, and the CDC doesn't recommend standard testing, so it's not always easy or cheap to do), then the risk from dating the average American is statistically greater (or similar depending on your condom usage) to the risk of dating someone with HSV-2 who takes all precautions . . .

[WCSDancer2010]

Also, if you do the math, the risk of getting HSV-2 from a person who knows they have it and takes all precautions . . . is significantly less than the risk of getting it from a person who hasn't been tested (most people haven't) and who doesn't take full precautions (most people don't) . . . using condoms 100% the time in both scenarios would bring the risk numbers close to parity

 

I've pointed this out to several guys I've dated... and they STILL didn't get it. I think many people...especially guys, just don't want to have to believe that they can't tell when a person has an STD... IE... they want to keep their head in the sand.... (sadly sand won't protect the other head either, but they don't get that either :p )

 

One problem with condoms is getting guys to wear them - esp the over 50's. Hate to tell you younger guys out there but condoms really can put a damper on the dipstick and most guys can't wear them for any length of time... at least, not without help from the little blue pill (and not all guys can deal with it... my last BF got severe headaches from it :( )

 

I can't wait for an opportunity to try the FC2 (female) condom... both because I'm tired of date night being me and my vibrator, but also because it seems like a really great alternative :)

 

[HerryTheHerp]

The only 100% effective way to prevent herpes transmission involves Vaseline and whichever of your hands isn't busy that night; and even then you might still get a blister.

 

You can do the math on it all you want. Bottom line? Life's a gamble. Personally, I'll take that gamble. Did I take it an acquire an incurable STD? Yep. Does it piss me off? Yep. Is there anything I can do about it now? Where's the Vaseline...

[rene]

WCS Dancer making me smile. Have you heard of the cupid female condom? I have bought one and I'm intrigued - apparently it'll be pink and vanilla scented when i take it out! I just hope the sensation is still there :/

I just had an outbreak on my inner thigh which was very painful. I now know I get it on my buttock and my inner thigh. I've even been worrying that I should not let my lover touch my thighs as that seems to be where H Loves to linger. It's so damn tricky trying to work out what to do. Crotchless bloomers? lol. I've decided to take acyclovir for a while as preventative.

 

[WCSDancer2010]

My understanding is that if anything, there is more sensation because the ring rubs near the clitoris... and it doesn't strangle they guys penis... so it *sounds* like a win-win O:-)

 

And the acyclovir sounds like your best bet - unless you are into role playing something from the Victorian era :p

[rene]

I'll let you know what it's like! That ring sounds good!

[JohnB23]

It's true, the only 100% way to avoid H is abstinence. But it does make me wonder if an undergarment of sorts would actually work (not that it would be practical or stylish). But if there's no contact of skin in the "boxer shorts area" then there's no way to transfer the H between people . . . perhaps it would only work for people with a real-deal affinity for latex, but preventing any skin contact just in that boxer short area should be100% effective (it wouldn't be too hard to design something that syncs with a condom (male or female) so that there are no gaps for skin to show) . . . but would anyone actually wear it?

[WCSDancer2010]

Uh... no... sorry... not here at least.

 

I want to be able to feel my partner... not a latex suit. Not into that kind of thing.

 

Once again, life/living implies risk. If you can't deal with risk, go live in a bubble. Or become a monk/nun. Don't get in a car - you may be killed. Don't go among people - you may get a communicable disease. Don't eat ANYTHING because you may get food poisoning/have an allergic reaction.

 

Sorry but I feel that our society has got to the point of stupid with our antiseptic/prophylactic craziness sometimes.... :p