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Antiretroviral Therapy for Prevention: An Alternative ( AND DYNAMIC) Perspective

Posted by plosmedicine on 30 Mar 2009 at 23:52 GMT

Author: Myron Cohen
Position: Director,Center for Infectious Diseases, University of North Carolina at Chapel Hill
Institution: The University of North Carolina at Chapel Hill
Submitted Date: April 11, 2006
Published Date: April 11, 2006
This comment was originally posted as a “Reader Response” on the publication date indicated above. All Reader Responses are now available as comments.

I read with great interest the modeling efforts of Baggaley and coworkers, which lead to the conclusion that antiviral therapy is unlikely to reduce the sexual transmission of HIV at the population level.

The results of this model are derived in part from assumptions about the probability of HIV transmission in subjects who receive therapy, how contagious subjects are when they receive their therapy, and how long and reliably they take their therapy.

The assumptions about the effects of antiviral therapy on transmission probability made by Baggeley may or may not be correct, but the field of research is certainly not static. The goals of ongoing studies are to improve our understanding of the effects of available antiretroviral drug combinations on sexual transmission of HIV, and to concommitantly develop drugs that benefit the health of the recipients, and prevent transmission.

Truly excellent progress has been made in defining drugs that concentrate in the male and female genital tracts, and that reduce HIV concentration in the genital tracts to undectable levels for long periods of time. The goal of this research is to identify the best possible ways to make treatment into reliable prevention.

Mathematical models are very helpful insofar as they make explicit many assumptions that are never articulated, and to generate hypotheses. Given the magnitude of the HIV pandemic, there is no way to develop too many prevention tools. Baggeley and coworkers
emphasize the critical role of sexual behavior in the spread of HIV, and no one would argue about the importance of risk reduction counseling. However, the goal of biologists working in this area must be to prove this model wrong (or unrealized) by developing antiviral regimens that reliably reduce HIV transmission to zero.

No competing interests declared.