April 3, 2012
Undetectable Viral Load? Not Necessarily in Semen
by Tim Horn
Undetectable viral loads in blood is not a guarantee that HIV is also undetectable in semen, according to a new study involving 101 HIV-positive men who have sex with men (MSM) conducted in Boston and published online ahead of print by the journal AIDS. Of the 83 men with undetectable virus in blood samples, roughly a quarter of them—21 MSM in total—had semen with detectable HIV.
Though the study conducted by Joseph Politch, PhD, of Boston University School of Medicine and his colleagues didn’t look at whether those with low-but-detectable levels of HIV in their semen were necessarily more likely to transmit the virus than those with undetectable seminal viral loads, the authors nevertheless caution that a risk of ongoing HIV transmission potentially remains in the absence of barrier protection during sexual activity. “Until more information on transmission risk in MSM is available,” they write, “it would be prudent to advise sexually active HIV-infected MSM to use condoms and other risk-reduction strategies throughout all stages of HIV disease regardless of HIV treatment status.”
Politch and his colleagues note that antiretroviral therapy is undoubtedly associated with a reduced risk of HIV transmission during sexual activity. In prefacing their own data, the authors reiterate the results of HPTN 052, which demonstrated that ARV therapy led to a 96 percent reduction in HIV transmission risk among HIV-discordant heterosexual couples, along with a study among MSM conducted over a decade ago concluding that HIV treatment decreases the transmission risk by roughly 60 percent.
Yet, according to the authors, “MSM have experienced a resurgent HIV epidemic in the [ARV treatment] era. Many HIV-infected MSM continue to engage in unsafe sex, and sexually transmitted infections (STIs) or other factors may promote genital HIV shedding and transmission in this population despite [ARV therapy].”
Though the “resurgent HIV epidemic” is undoubtedly multifactorial—roughly 20 percent of those living with HIV, including many MSM, are not aware they are infected and have thus not received personalized care and counseling—Politch’s group set out to explore an important factor associated with HIV transmission: the prevalence of seminal HIV shedding among HIV-positive MSM receiving ARV therapy, and how it relates to a number of clinical, behavioral and biological variables.
The study recruited HIV-positive participants from Fenway Health, a clinic catering to the health care needs of the lesbian, gay, bisexual and transgender community in Boston. Paired blood and semen samples were collected from the 101 study volunteers. Clinical and behavioral data were obtained from medical records and questionnaires. Evidence of genital herpes and genital inflammation were also assessed using laboratory tests.
The men were predominately white (74 percent), and virtually all (97 percent) identified themselves as MSM. The average age of the study volunteers was 43. Eighty percent had been on ARV therapy for more than a year; all had been on HIV treatment for at least three months.
Twenty-seven percent reported only engaging in protected sexual intercourse within the three months before study enrollment and were thus classified as low risk for acquiring a sexually transmitted infection (STI). Seventy-three percent were classified as high risk for having an STI, based on self reports of unprotected sexual intercourse in the past three months.
Nine men, all belonging to the high-risk group, tested positive for an STI within seven days before their official start in the study. Sixty-three percent of the men were positive for genital herpes, or herpes simplex virus-2, HSV-2, antibodies.
Eighteen of the 101 MSMs enrolled in the study had detectable HIV in their blood samples. The average viral load among these men was 560, but it ranged from 80 to more than 600,000. Nine (50 percent) of the men with detectable blood-based viral loads also had detectable HIV levels in their semen.
Eighty-three of the 101 MSM had undetectable levels of HIV in their blood samples. Though most also had undetectable HIV in their semen samples, 21 (25 percent) had detectable seminal viral loads.
Politch and his team note, however, that HIV levels—free-floating HIV-RNA and both HIV-RNA and HIV-DNA in cells—were significantly higher among those with detectable blood-based viral loads, compared with those with undetectable blood-based viral loads. For example, whereas the average free-floating viral load was 4,438 copies among those with detectable blood-based HIV levels, it was 51 copies among those with undetectable blood-based HIV levels.
Whether or not the free-floating virus detected in the semen samples of those with undetectable blood-based viral loads is of high enough quantity and/or quality to establish infection in a sexual partner wasn't explored by the researchers.
The authors did note, however, that the prevalence of HIV shedding among those with undetectable blood-based viral loads documented in this study proved higher than has been reported in other studies. “This is likely due to the high prevalence of STIs and genital inflammation in our sexually active MSM cohort.”
Indeed, among the three factors associated with having detectable seminal viral loads among those with undetectable blood-based levels, having an STI was associated with a 29-fold increase in the risk, compared with those who didn’t have an STI. Being positive for HSV-2 was not associated with have a detectable seminal viral load.
As for the other two factors, genital inflammation—notably an increase in tumor necrosis factor-alpha, an inflammatory marker—was associated with a 14-fold increase in the risk, whereas unprotected insertive anal sex with an HIV-positive person—“topping” a positive partner without a condom—was associated with a sevenfold increase in the risk of having detectable HIV in semen even when HIV is undetectable in blood samples.
“In light of recent evidence that even low amounts of HIV in semen could pose a transmission risk in MSM, who are more vulnerable to HIV infection than heterosexual men, this information has potential clinical significance for the HIV epidemic in MSM,” the authors conclude. “HIV-infected men who engage in unprotected intercourse may use [ARV therapy] and viral load status in their sexual decision-making, and being on [ARV therapy] or having an undetectable blood viral load may relax concerns about transmitting HIV. Therefore, MSM at risk for transmitting HIV may believe that they have a low risk based on incorrect assumptions that [ARV therapy] eliminates HIV from semen.”
Of particular concern to the study investigators is that ongoing replication of the virus in the genital tract, in the presence of ARV therapy, can lead to the accumulation of drug-resistance mutations and the possible spread of treatment-resistant virus. This, they point out, "may contribute to the high prevalence of antiretroviral drug-resistant HIV in HIV-infected individuals in the United States [who have not yet started ARV therapy]."
In addition to the suggestion that condom use continue to be promoted as a harm-reduction strategy among HIV-positive MSM who are otherwise responding well to ARV treatment, the authors also note the need to “promote the aggressive diagnosis and treatment of STIs.”
Search: hiv, semen, genital, viral load, transmission, prevention, gay, men who have sex with men, msm, fenway, boston
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comments 1 - 15 (of 21 total) next
Gus Cairns, London, 2014-11-05 03:25:52
"...Whereas the average free-floating viral load was 4,438 copies among those with detectable blood-based HIV, it was 51 among those with undetectable blood-based HIV".
Does anyone think a viral load of 51 is enough to infect anyone? There have been few suggestions, let alone cases, of anyone getting infected from a viral load below 500 copies. The stuff about STIs is probably irrelevant too; for instance there was no association between having an STI and infecting anyone in PARTNER.
Steve, , 2013-11-13 11:47:42
The statement, Whether or not the free-floating virus detected in the semen samples of those with undetectable blood-based viral loads is of high enough quantity and or quality to establish infection in a sexual partner wasn't explored by the researchers.
Up until now, many researchers, especially citing the Swiss study, have said unprotected oral sex is relatively safe as long as the HIV+ partner is undetectable. You can't have it both ways, so which is it, risk or virtually NO risk?
Shereeug, Baltimore, Maryland, 2013-06-17 03:01:22
The data is rather exciting.
Frank, San Francisco, 2013-01-27 01:46:48
The key point here-one left unanswered-is the importance of the "quality and quantity" of HIV in seminal fluid.The presence of HIV in semen,does not ipso facto make it infectious.Other studies,most noteably the Swiss study, have found transmission all but impossible with undectable blood viral loads.
Tom, USA, 2012-11-03 21:30:43
There is a danger in using data that is undefined and counter productive in its scientific value. For every study you find that is improperly conducted there are many more that are flawed and unproductive. It is improper to arrive at a consensus without any truly empirical data. As with any situation of unknown quantity, it is always best to be safe, this type of unfounded data is a sad reminder of bias.
Anonymous, Manhattan, 2012-07-21 11:37:03
I'm glad to see so many are acutely aware of the facts and the background of such studies. Fact - the difference between infective hiv "cells" and non-infective has been known for a long time and each are easily identifiable. The failure to specifically identify if the cells are infectious must therefore be deliberate. The motive is of course the US's long standing eugenics programs which started pre WWII and encouraged, complemented and copied many of Hitler's eugenics efforts. Sheesh
mark, , 2012-06-25 20:38:04
ever wonder if its the christian right-wing groups that are sponsoring so-called 'studies' like this that are just designed to create more fear and to further stigmatize hiv infection? is there not enough of a divide for them already?
Thom, USA, 2012-05-23 22:25:28
Why do scientists do this? Assume that data tells a story without knowing the true indication of the situation, there are so many variables that might effect this outcome that you really cannot be sure of anything, seriously, this study is totally bogus it does not even cover the basics of research and development procedures, which leaves me with the question Why?
What is the interest of the party that has published this?
Is there some political method to this madness?
One thing seems clear )
Long Time Survivor, , 2012-04-24 05:15:10
I tested poz in 1985 when the blood test became available. I was sure in 1983 I was infected and believe infection occurred in 1982. I have had an undetectable viral load for 15 years with no break throughs. I only bottom. Is it fair to assume which I do, since I don't give loads but do bottom bb that the risk to a neg top is virtually nil? I liken it to the risk of being hit by a Mack Truck while crossing the street. It exists but the risk is infinitesimally low. Do I not cross the st?
Brian, Beantown, 2012-04-13 08:26:18
The original Lancet study on sero-divergent couples (father pod, mom neg) showed a 0 percent infection rate for inseminations (holds to this day and over 10,000 world wide done). I was part of couple 39 in the first study and have 2 children from this study. The samples were tested and I was told mine tested undetectable for any virus-PCR methods at that time are unclear to me. The samples are frozen and would provide a perfect large study cohort-I am undetectable but "safe" never-use condoms!
David, San Francisco, 2012-04-10 23:43:39
“it would be prudent to advise sexually active HIV-infected MSM to use condoms and other risk-reduction strategies throughout all stages of HIV disease regardless of HIV treatment status.” This statement is bullsh*t! Sex is between two individuals. BOTH have a responsibility to their own health and each other. One-sided recommendations only fuel the stigma fire faced by HIV-infected individuals.
burn, birmingham, 2012-04-10 08:51:31
This really didnt tell us anything new and seems unhelpful... more information we have the better but I think we can all agree the basics of safe sex still stand between honest and consenting poz4poz as less managed by the medical community and this study lays weight only toward poz4neg.
Andy, , 2012-04-06 20:45:36
Jalke, I think condoms are a great idea for a lot of things other than just HIV. Keep using rubbers! What offends me about this study is that a lot of the stigma we face stems from the idea that we're "dangerous". This study, which i'm sure is paid for with limited public funds, implies danger without proving it, then uses that assumption to imply that people who know their status are the ones driving infections. Its stigma pretending to be science, which I'm seeing a lot of these days.
Jalke, New York, 2012-04-06 08:00:36
I would agree with most other comments that this is just more hysterics designed to intimidate people into using condoms. Anytime a study concludes there a minimal risk of transmission, as several other studies have, someone has to go and point at conjectures and "possible risks" to keep the fear out there. Also, by continuing to call it "unsafe" sex vs. "unprotected" sex they stir up panic. Spend the money to find a freaking cure instead!
Andy, , 2012-04-05 09:44:08
comments 1 - 15 (of 21 total) next
So the study implies, but does not establish, that poz men are dangerous. Then, we're admonished to stop putting others at risk, ignoring the fact that it takes two for sex. So this is basically serophobia masquerading as "prevention science". Looks like another low point for "prevention".
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