December 18, 2013
Sax's counterargument largely revolved around a desire for what he considered a more realistic approach to prevention set within the modern context of the epidemic. In the early 1990s, when Sax and Gulick were both fellows at Massachusetts General Hospital, AIDS was a leading cause of death among youth and one of their mentors "basically made us feel that having unprotected sex was the equivalent of a death sentence," according to Sax.
"What Trip is telling you is that he's a product of his time," he said. But what the data show -- "in humans ... not in laboratory experiments, not in models" -- is that the actual HIV transmission rate from a virologically suppressed, HIV-infected person to an HIV-uninfected partner is "essentially zero," Sax asserted.
Sax cited a systematic review of 11 cohort studies that found zero cases of HIV transmission from an HIV-infected partner to an HIV-uninfected partner when the HIV-infected partner's viral load was below 400 copies/mL -- even if the partner was not on antiretroviral therapy.
Sax also referred to the well-known "Swiss statement," a landmark 2008 publication by highly respected clinician-researchers in Switzerland that unequivocally supported the argument that HIV cannot be transmitted sexually by an HIV-infected person who is fully compliant with therapy, is monitored by an attending physician, has had an undetectable viral load for at least six months, and has no other sexually transmitted diseases. "Precision, orderliness ... those are some of the things that come to mind when you say 'Switzerland.' You do not think, 'Oh, they are going to give irresponsible statements about public health,'" Sax said. "And you'll note that the people on this statement were people who are leading figures in our field of HIV research."
Sax also called attention to the 2011 publication of results from HPTN 052, which he suggested may be the most important HIV prevention study to date. That study (a randomized investigation comparing HIV transmission rates in early versus late treatment initiators who were in serodiscordant relationships) found seven cases of transmission in the delayed therapy group, but only one in the early treatment group -- and that single case occurred prior to the patient achieving virologic suppression.
Not that HPTN 052 was the only study to see such findings; Sax noted several additional studies published between 2008 and 2011 -- elucidated in a PLoS One article earlier this year -- showing a nonexistent transmission rate among patients with an undetectable viral load.
"Protection for these individuals is no longer needed," Sax concluded. "Are we actually going to be taking no risks in our life? ... Unprotected sexual intercourse is a viable option -- I'm not saying recommend that they stop using protection, but it's up to them -- for serodiscordant couples in long-term, monogamous relationships."
Where do you stand on the issue? The audience present at this debate -- a collection of infectious disease clinicians and researchers -- overwhelmingly sided with Gulick's assertion (by a margin of 63% to 37% among those who voted via remote controls located near many seats) that serodiscordant couples should perpetually take preventive measures to curb the risk of HIV transmission. But surely that won't be the final word on this challenging, complicated question.
Myles Helfand is the editorial director of TheBody.com and TheBodyPRO.com.
Follow Myles on Twitter: @MylesatTheBody.
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