The Challenges of Treatment as Prevention Among MSM
The Challenges of Treatment as Prevention Among MSM
Last year's HIV Prevention Trials Network 052 study documented substantial reductions in HIV transmission to partners by persons living with HIV who had initiated early antiretroviral treatment. The study's initial findings revealed that just one new HIV infection traceable to a treated partner occurred in the early treatment arm, whereas 27 such new infections occurred in the delayed treatment arm. This difference represents a 96 % reduction in new infections amongst partners of those who took antiretroviral treatment throughout the entire course of the study. Seeking to meet the National HIV/AIDS Strategy goal of reducing new infections 25 % by 2015, the Centers for Disease Control's new High Impact Prevention approach for the United States now prioritizes expanded HIV testing and antiretroviral treatment. Even before the release of HPTN 052 results, expanded HIV screening and treatment in the U.S. had been modeled to be cost effective, though only moderately successful in reducing new infection rates. Recently, HPTN 052's principal investigator noted "The HPTN 052 trial demonstrated nearly complete prevention of HIV transmission by early treatment of infection, but the generalizability of the results to other risk groups-including injection drug users and men who have sex with men (MSM)-has not been determined".
Nearly all participants in the HPTN 052 study were heterosexuals (98 %) enrolled from low- and middle-income nations (97 %). As one entry criterion for HPTN 052, HIV-negative persons were required to have been involved in a stable relationship with their HIV-positive partner for at least 3 months. Of the participants ultimately enrolled, 94 % were married, and less than 5 % had a sexually transmitted infection at enrollment. Nearly all HIV-negative partners enrolled in the study were monogamous (96 and 97 %, in the early and delayed therapy arms respectively) throughout the study's mean 1.7 year duration. These HIV-negative participants reported sexual relations with only one partner, whose HIV treatment was monitored. By contrast, Reynolds et al. previously found no significant decline in numbers of outside sexual partners reported by persons in a relationship in which a partner living with HIV had initiated Highly Active Antiretroviral Therapy. Recognizing the importance that relationship status plays in antiretroviral treatment as prevention (TasP), El-Sadr et al. predicted greater success in decreasing HIV incidence when populations had a higher proportion of stable partnerships. However, the CDC's High Impact Prevention approach focuses on diagnosis and linkage to care, and does not yet incorporate assessment of monogamy versus sexual concurrency (having overlapping sexual partnerships) in at-risk MSM populations.
We maintain that sexual monogamy and awareness of partner's status likely contributed substantially to the 052 study's success with TasP, and that this entry criterion may have biased the study outcomes towards more promising results. Prevailing relationship practices among MSM will likely undermine the potential preventive effect when attempting to utilize TasP to significantly curb the U.S. epidemic.
Abstract and Introduction
Introduction
Last year's HIV Prevention Trials Network 052 study documented substantial reductions in HIV transmission to partners by persons living with HIV who had initiated early antiretroviral treatment. The study's initial findings revealed that just one new HIV infection traceable to a treated partner occurred in the early treatment arm, whereas 27 such new infections occurred in the delayed treatment arm. This difference represents a 96 % reduction in new infections amongst partners of those who took antiretroviral treatment throughout the entire course of the study. Seeking to meet the National HIV/AIDS Strategy goal of reducing new infections 25 % by 2015, the Centers for Disease Control's new High Impact Prevention approach for the United States now prioritizes expanded HIV testing and antiretroviral treatment. Even before the release of HPTN 052 results, expanded HIV screening and treatment in the U.S. had been modeled to be cost effective, though only moderately successful in reducing new infection rates. Recently, HPTN 052's principal investigator noted "The HPTN 052 trial demonstrated nearly complete prevention of HIV transmission by early treatment of infection, but the generalizability of the results to other risk groups-including injection drug users and men who have sex with men (MSM)-has not been determined".
Nearly all participants in the HPTN 052 study were heterosexuals (98 %) enrolled from low- and middle-income nations (97 %). As one entry criterion for HPTN 052, HIV-negative persons were required to have been involved in a stable relationship with their HIV-positive partner for at least 3 months. Of the participants ultimately enrolled, 94 % were married, and less than 5 % had a sexually transmitted infection at enrollment. Nearly all HIV-negative partners enrolled in the study were monogamous (96 and 97 %, in the early and delayed therapy arms respectively) throughout the study's mean 1.7 year duration. These HIV-negative participants reported sexual relations with only one partner, whose HIV treatment was monitored. By contrast, Reynolds et al. previously found no significant decline in numbers of outside sexual partners reported by persons in a relationship in which a partner living with HIV had initiated Highly Active Antiretroviral Therapy. Recognizing the importance that relationship status plays in antiretroviral treatment as prevention (TasP), El-Sadr et al. predicted greater success in decreasing HIV incidence when populations had a higher proportion of stable partnerships. However, the CDC's High Impact Prevention approach focuses on diagnosis and linkage to care, and does not yet incorporate assessment of monogamy versus sexual concurrency (having overlapping sexual partnerships) in at-risk MSM populations.
We maintain that sexual monogamy and awareness of partner's status likely contributed substantially to the 052 study's success with TasP, and that this entry criterion may have biased the study outcomes towards more promising results. Prevailing relationship practices among MSM will likely undermine the potential preventive effect when attempting to utilize TasP to significantly curb the U.S. epidemic.