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Will Your Next Viral Load Be as Undetectable as the Last? Study Says: Probably

June 10, 2009

If your past several viral load test results have been undetectable, there's about a 95 percent chance that your next one will be, too, according to a large Swiss study published in the May 6 issue of HIV Medicine, the official journal of the British HIV Association. The new findings may reignite the debate over just how likely people with HIV are to transmit the virus if their HIV viral load has been consistently undetectable while they were on treatment.

The Background

That debate exploded in January 2008, when the Swiss Federal Commission for HIV/AIDS released a controversial report for Swiss physicians. The report examined a series of studies involving heterosexual couples in which one partner was HIV positive and the other was HIV negative (called "magnetic" or "serodiscordant" couples). The report stated that it was almost impossible for a heterosexual, HIV-positive person on HIV meds to pass HIV to his or her partner during unprotected sex, provided the HIV-positive person:

  • was in a "stable relationship" (meaning he or she had no other partners)
  • was on an approved antiretroviral therapy regimen;
  • was taking all of his or her HIV meds properly;
  • had an undetectable viral load for at least six months; and
  • had no other sexually transmitted diseases.

Most of those finer points were lost when the story went public, however. Headlines screamed that the commission was giving HIV-positive people a nearly unequivocal green light to have unprotected sex. (The venerable Agence France-Presse may have taken the oversimplification cake with "Patients on AIDS Drugs Don't Transmit Virus.") Accusations flew, the researchers came under fire, clarifications were issued, and ultimately the furor died down.

But the question remains: Are there cases in which HIV-positive people can have unprotected sex with their HIV-negative partner without having to worry about the possibility of transmitting HIV?

Central to answering this question is the issue of exactly what it means to have an "undetectable" viral load. Any number of things can happen during the three-month span that usually passes between a person's viral load tests, such as an interaction with a new herbal supplement, prescription medication or over-the-counter drug. And sometimes, albeit rarely, a person's viral load can briefly spike for reasons that are still unknown.

But what are the chances that any of these things will happen? If a person had an HIV viral load test two months ago and it found her or his viral load was undetectable, what are the odds that's still the case now?

The Study Findings

This study was conducted by some of the very researchers who were at the center of the Swiss Federal Commission brouhaha. In fact, three of the researchers -- Pietro Vernazza, M.D., Bernard Hirschel, M.D., and Enos Bernasconi, M.D., all prominent Swiss HIV experts -- had been co-authors of the very report that ignited the controversy in January 2008. The study's primary author was Christophe Combescure, Ph.D., of the Division of Clinical Epidemiology at University Hospital Geneva.

The thrust of the study was an examination of viral load test results in 6,168 people participating in the Swiss HIV Cohort Study. All were HIV-positive people who had at least one viral load test result below 50 copies/mL (the lowest level at which commonly used viral load tests are able to detect HIV) between May 2003 and December 2007 while they were taking HIV treatment. Some other quick facts about the participants:

  • About 69 percent were men.
  • About 39 percent said they got HIV through heterosexual sex.
  • Nearly 37 percent said they got HIV through sex with another man.
  • Nearly 21 percent said they got HIV through injection drug use.
  • About 82 percent were white.
  • The average age was 41.

Unsurprisingly, the researchers found that the more undetectable viral loads a person already had, the more likely it was that her or his next viral load would also be undetectable. But there was a limit. A person with one undetectable viral load had an 84.5 percent chance of his or her next viral load being undetectable. The odds rose steadily to 94.5 percent for people with five undetectable viral loads -- and then remained at around 95 percent for people with more than five undetectable viral loads.

When they looked at the reasons why people developed a detectable viral load, the researchers found (unsurprisingly) that having missed more than one dose of HIV meds in the past four weeks was a major factor. They also found that a detectable viral load was more likely to occur among people who were on HIV meds but who were not taking combination HIV treatment, also known as HAART.

Interestingly, the Swiss study also noted that the specific clinic that an HIV-positive person went to impacted her or his odds of maintaining an undetectable viral load. The researchers suggested this might be because centers use different procedures to conduct and analyze viral load tests, possibly causing variation in the test results.

The Takeaway

Do these results help or hurt the argument that it can sometimes be "safe" for some HIV-positive people to have unprotected sex with their HIV-negative partners? Despite their deep involvement in the controversial Swiss statement of January 2008, the researchers avoid making any definitive claims in this study. The closest they come is this somewhat ominous line within the study's conclusion: "Our data leave open the possibility that unexplained high [viral loads] in seemingly well-controlled patients, although rare, can occur."

Are those odds low enough to warrant having sex without protection? The researchers avoided giving an opinion on the issue. But we hope that won't stop you from offering your take.

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This article was provided by TheBody.
See Also
Resistance/Viral Load & Transmission

Reader Comments:

Comment by: Greg (Melbourne Australia) Sun., Feb. 27, 2011 at 5:44 am UTC
I am newly diagnosed, and have an undetectable viral load 3 months after diagnosis, and it is so tempting to throw away the condoms, I am not in a relationship, however with the stigma here in Melbourne about being HIV - I figure that undetectable or not, the risk of transmition, is still transmition, and now each time i meet someone who im like gee they are hot, the HIV creeps up, in my mind and its like great, their is a deal breaker
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Comment by: TK (San Francisco) Wed., Sep. 15, 2010 at 12:19 am UTC
It's a very personal decision. The best we can do is have as much information as possible. I share my story not to condone one behavior or another. I'm positive; my partner is negative. We've been having unprotected sex for 7+ years with me as top. I have never ejaculated inside him. He is tested yearly if not more and has always remained negative. This could be related to the undetectable viral load or more likely to that plus a combo of factors: We're monogamous (no STIs), no ejaculation, and we're both healthy. A very small percentage of people cannot get HIV. Maybe he has that gene (google it)? So I'm not condoning but sharing my life details. Good luck with whatever choice/risk you take.
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Comment by: JC (Chicago) Fri., Jul. 23, 2010 at 10:55 pm UTC
I'm in a magnetic relationship and have been for 8 years now. There are many times when we get weak and want to bareback. However, this is just one of the things we will never be able to do and would rather a company invest in making a better condom than we take the risk. I am (+) and he is (-). I love him dearly and would not take that chance just for 12 mins of barebackin'. I really wonder the percentage of people that have tried to take the risk infected another person? I would love to hear from them.
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Comment by: Lolly (South africa) Sat., Jun. 12, 2010 at 12:41 pm UTC
I had two undetected viral load and my partner is hiv negative,is it safe to get pregnant we are not using protection for the past 6months
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Comment by: BL (Perth, Western Australia) Wed., Feb. 3, 2010 at 1:54 am UTC
I've had an undetectable viral load every 3 month test/15+ years. From my experience in this city, there is much ignorance/stigma about hiv/aids; disclosing hiv+ status before sex puts safe(with condom)sex off the agenda,hand only sometimes oral. Many stats show a major percentage of new infections are from persons not on treatments, un-diagnosed, or newly diagnosed.
Isn't this new information on 'minimal transmission with no viral-load' a way to encourage newly diagnosed onto treatments, and educate the broader community about harm reduction, safe/r sex, - and toward dispelling anti hiv+ myths and bigotry?
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Comment by: Mandisa (London) Mon., Jan. 18, 2010 at 9:17 am UTC
Ive been positive for 11 yrs now not on Meds and still undetectable,Ive just met a neg partner,The study didnt mention people like me who are not on meds,any one with clearity plz?
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Comment by: Danny (Manchester, England) Fri., Jan. 1, 2010 at 9:05 pm UTC
The facts are clear...your are non-infectious when you have been undetectable for 6 months...if you are not sure have your sperm checked to see if your blood corresponds with your genital tracts. Atripla usually does penetrate the genital tract well..the few who were undetectable and had so in their semen are the rare ones. YOu need to check if your drugs penetrate your genital tract the same as your blood count.. if it does then you are fine as long as you have no sti's. If you are unlucky enough to be the rare person who doesnt where the meds dont penetrate the genital tract the same as their blood...then you wear a condom...just have your sperm checked to see if your meds do the same to your genital tract as your blood and then you ll know
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Comment by: John (East Coast) Thu., Dec. 17, 2009 at 1:33 pm UTC
I took a foolish chance with someone I am dating, who is HIV+ (I am HIV-). I had unprotected sex with him (me as the top), thinking there was a low risk. There probably is a low risk, but no past or future study can assure anyone of safety as a condom can. There was so much about this whole thing that's been a mistake, and I'm worried sick about it. I think most transmissions of HIV are from events that could have been avoided. Several friends of mine are HIV+, and I don't know any of them who said that what they did to contract it was worth it. Ignorance and feeling that we are invincible is what is keeping us from tackling this HIV epidemic!! Don't be foolish and force yourself to live with a mistake that will change the rest of your life, as I may have done.
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Comment by: Harold (Washington) Tue., Sep. 29, 2009 at 2:44 pm UTC
I just met a gorgeous guy who is a bottom and HIV positive with undetectable viral load. I am a top. It is so tempting to bareback him. I am going to have to do some serious thinking.
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Comment by: Dan (Charlotte, NC ) Sat., Jul. 18, 2009 at 4:53 pm UTC
Personal Stats-My partner is HIV+ and has been undetectible since we've dated 4 yrs now. I'm a top and used condoms seldom and still tested negative. I hate condoms but I'm learning to deal with it. I think the risk is low but not low enough it only takes once.
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Comment by: Modikane (Pretoria, South Africa) Wed., Jul. 8, 2009 at 3:17 pm UTC
My wife and I lately occasionally omit the condom. She HIV+ and me HIV-. I figured the risks have been reduced since her viral load is undetectable for a while now. It is a conscious decision to occassionally forget the condom.

No doctor nor scientist will ever open the floodgates and say go ahead it is safe to have unprotected sex, since there still are risks. Even if the risks are less than 1, no one would ever want to have to answer on statements they declared.
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Comment by: i (ny ny) Thu., Jun. 18, 2009 at 12:19 pm UTC
I am negative my partner positive. Please wear a condom its better safe then sorry.
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Comment by: JB (Dallas) Mon., Jun. 15, 2009 at 12:55 pm UTC
My partner is HIV+ and has been undetectable for many years. When I met him 2 years ago I was HIV-. I am only a top and I decided to not use condoms... I am now HIV+.
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Comment by: Steve (Glendora Ca) Sun., Jun. 14, 2009 at 11:30 pm UTC
I have met someone with HIV poz/ I am unfamiliar as to how to be intimate with him. I am negative. I like him and want to know more about intimacy with a POZ person and not get infected.
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Comment by: Terence (London) Sun., Jun. 14, 2009 at 7:27 am UTC
Totally agree with Jeremy England. I always use condoms but unfortunately one of the guys I have sex with decided that he would take the risk and removed the condom during sex, unknown to me until after he had ejaculated. Guess what. I am not HIV/HepB coinfected, even though I religiously went to have boosters against HepB. So use a condom. You're worth it. Love to all
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Comment by: Josie (NYC) Sat., Jun. 13, 2009 at 10:00 pm UTC
After being diagnosed in January, my negative partner will not have sex with me at all, with or without a condom. I try to explain to him that with my status being undetectable, as well as us wearing a condom, he will remain negative. He doesn't want to hear it though!
Reply to this comment

Comment by: lara (washington dc) Sat., Jun. 13, 2009 at 8:04 am UTC
I have HIV+ and undetectable. My partner is negative and initially used condoms but now we no longer use them (his decision). I take my meds religiously and take very good care of myself. I honestly believe the swiss study.
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Comment by: samantha (silver spring,maryland) Sat., Jun. 13, 2009 at 8:00 am UTC
I think the decision to have unprotected sex in a magnetic couple is a very personal and private decision.I feel that if a person is undetectable and continues to be so then if the negative partner feels that he/she is willing to take that tiny risk then it is up to them.
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Comment by: rmk (conn) Sat., Jun. 13, 2009 at 4:28 am UTC
In a perfect world, the information on HIV would encourage safe sex, but such a world is not one we inhabit. As long as people are going to bb is it not just as responsible for them and science to give them as much valid information to at least go on meds asap and reduce the risk. Perhaps this will lead to more open discussions on status, perhaps not, but at least those on meds will reduce thier infection rate of others perhaps by a 95% rate This in the long run will reduce the overall new rate of infections. There will always be someone who does not know or does not want to know or perhaps care, but for those of us who do being armed with reliable information could make a difference in disclosure, which at least lets people decide risk for themselves. Wishing people would not act in one way does not mean we should put our heads in the sand and ignore reality as it is.
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Comment by: Bob (Brenham, Texas) Fri., Jun. 12, 2009 at 9:27 am UTC
I have been HIV+ for nearly 10 years and undetectable since initiating HAART during my initial infection. I protect my partner of 3+ years by always wearing a condom while inside him, but hope for the day that there will be a chance to dispense with them. They diminish the pleasure tremendously, and we lose the opportunity for the greater intimacy that unprotected sex would afford. I am clear on my responsibility, though!
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Comment by: Tom (Mpls, Mn) Fri., Jun. 12, 2009 at 9:04 am UTC
Don't use them. The study confirms what I've observed over many years. This study flies in the face of the Condom Nazis.....that's what they don't like !!!
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Comment by: Jeremy (england) Fri., Jun. 12, 2009 at 5:22 am UTC
What's the problem with wearing a condom ? I can assure anyone that the " lost pleasure " will be far outweighed by the feeling of wellbeing after the act is over, that you have done everything possible (short of not having sex) to prevent the spread of infection to a fellow human being, and all the awful repercussions that this could incur, for them and for you. Get real people and get a little bit less selfish !
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Comment by: Robin (Easton) Thu., Jun. 11, 2009 at 10:59 pm UTC
My wife and I occasionally have unprotected sex. She is HIV positive, I am negative. She has been undetectable for 3 years. We usually use condoms, but condom are not like feeling inside of her. So once in a while we don't. What the hell. It's comforting to know that I'm not at great risk when we omit the condom. I mean, when she was infectged the CDC was advising against deep kissing and that didn't stop us from doing that.
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Comment by: alg (Salt Lake City, Utah) Thu., Jun. 11, 2009 at 1:23 pm UTC
I have had an undetectable viral load for 15 years + and my partner is not positive nor will he ever be due to I wear condoms. How could you not?
You love this person so why put them at risk. Put the glove on, it does not matter what any study says.
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