NATAP: Swiss statement on HIV transmission

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http://www.hopkins-hivguide.orgSwiss statement on HIV transmission Posted on Feb 8, 2008Dear doctor Gallant, What is your opinion on the Swiss standpoint that someone with HIV who is on therapy, with great adherence, has an undetectable viral load longer than 6 months and doesn't have an other STD has a very low chance to infect his partener by sex without wearing a condom? A risk so low that it is comparable with taking a plane (a plane can crash)? Regards, Kees In German: http://www.saez.ch/pdf_d/2008/2008-05/2008-05-089.PDFOn Feb 9, 2008  E. Gallant, M.D., M.P.H. replied:Kees, I agree that the risk is extremely low; I couldn't say whether it's comparable to the risk of flying in plane(depends on the airline, I guess! If the Swiss made that analogy, it's an unfortunate one in light of the infamous Swissair crash.) However, before you throw away the condoms, there are several things to consider: 1. There's a lot of bad stuff being passed around out there, including infections that can increase your risk of HIV transmission, such as syphilis and herpes. These infections can be prevented with condoms. 2. We know that you can have an undetectable viral load in your blood but a detectable viral load in semen or vaginal fluid, so it's still theoretically possible to transmit with an undetectable viral load. 3. Your viral load doesn't get measured every day, and people DO sometimes fail therapy. How can you be sure that your viral load is still undetectable today just because it was 3 months ago. I still believe in condoms for intercourse in most situations, especially when the positive partner is on top. In the case of a monogamous discordant couple who wants to consider unprotected sex, we talk about the risks, however small. There's no right or wrong answer--people have to make up their own minds about the amount of risk they're willing to accept.Posted on Feb 10, 2008Dear Dr Gallant I too was of the same opinion of infection thru' unprotected sex in UD cases, but recently saw the articles as below 1)http://timesofindia.indiatimes.com/Semen_makes_HIV_more_deadly/articleshow/2736834.cms 2)http://jama.ama-assn.org/cgi/content/full/299/3/279-b 3)http://www.aidsmap.com/en/news/167784F9-FD3C-4148-8AB3-F669FE941BB3.asp 4)http://www.papamamanbebe.net/a8205-patients-treated-for-hiv-with-undetectable.html The simple point is that even if you are otherwise completely symptom free and have no other STD's etc ,, it is the specific properties of one's semen, which I suppose itself varies from time to time which can make it upto 100,000 more times tranmissble with even just the presence of 3 hiv virons in a normal volume of ejaculate Ultimately as you said everyone has to choose their own risk appetite, and try and make sure that they are atleast truly undetectable and not failin g therapy.On Feb 15, 2008  E. Gallant, M.D., M.P.H. replied:The first two articles refer to fascinating data discussed at CROI suggesting that a substance found in prostatic fluid (and ultimately in semen) directly enhances HIV transmission. However, these findings do not mean that transmission can occur with an undetectable viral load in semen. The third points out that viral load in semen can be detectable when it's undetectable in plasma. We've known this for some time, and it's an argument against the Swiss approach, though it still does not mean that people with undetectable plasma viral loads are transmitting HIV. The fourth is a fascinating debate on the subject.Posted on Feb 14, 2008Thank you very much Dr. G for all that you do. Your answer raises a number of questions in my mind: 1. Is there any evidence that there has ever been a proven case of transmission when it is sure that the person has an undetectable VL at the time of transmission? I make a distinction between a known and actual undetectable VL at the time of the transmssion and a dectectable VL that may have emerged, through a lapse in compliance or "failure" of treatment. 2. Does the longer a person bas been compliant and maintained an undetectable VL have any bearing on the risk of transmission? What is the actual empirical evidence? 3. Is it possible (and practical) to test semen and other body fluids? Say a person has maintained an undetectable VL in the blood for at least six months (or other period you would be comfortable with), could it be possible to test semen and/or other body fluids? 4. The notion of "risk" is not clear to me in this context, it strikes me as better to speak in terms of "probability" based on actual observed experience and the empirical evidence to back up the assigned probability of an event. Could you please address this point in the context of monogamous discordant couples.On Feb 15, 2008  E. Gallant, M.D., M.P.H. replied:1. Not that I'm aware of. 2. Probably. The longer a person has been compliant with an undetectable viral load, the less likely they are to rebound between viral load measurements. 3. It's possible, but hardly practical. 4. The difference between "risk" and "probability" is one of semantics. I believe I already addressed the issue for monogamous discordant couples in my first response.Posted on Feb 17, 2008Note that all the studies cited in the Swiss review refered to vaginal sex (with the excpetion of the SF study which was ecological). I happen to agree with the Swiss researchers (and with you -- in sex as in the stock market we each get to decide how much risk we are willing to take, see http://www.wisdomofwhores.com/2008/02/05/to-inform-or-to-overprotect-the-swiss-have-chosen-well/ But: do we have any evidence at all about the risk of transmission for people on treatment in higher-per-act transmission risk behaviours -- unprotected insertive anal sex and sharing of needles? The Swiss statment appeared to cover the former but not the latter, but I'm not aware of evidence in either area.On Feb 18, 2008  E. Gallant, M.D., M.P.H. replied:The risks from unprotected receptive anal and vaginal sex are both high. What applies to one probably applies to the other. The risk from using needles and syringes that contain infected blood is even higher. However, at least with this mode of transmission, you don't have to worry about the potential disconnect between plasma viral load and vial load is genital secretions. On the other hand, I don't have too many patients who have persitently undetectable viral loads despite actively injecting drugs--it happens, but it's uncommon.