Vaccine and Infectious Disease Division

ART dampens HIV transmission

The Partners in Prevention study looked at nearly 3,400 African couples where one partner had both HIV-1 and HSV-2, and the other partner was HIV-negative.  While the primary endpoint of the study, a test of whether the anti-herpes drug acyclovir would decrease transmission of HIV to the uninfected partner, did not show a significant change, this study is by far the largest study of partners with differing HIV status and as such provides a unique opportunity to explore many facets of HIV transmission.  In a recent analysis, VIDD senior staff scientist Dr. Deborah Donnell and colleagues asked whether anti-retroviral therapy (ART) affected HIV transmission.

Previous studies have shown that higher viral loads in the blood are linked with higher rates of transmission, and ART is known to significantly decrease viral load.  ART given during pregnancy to HIV positive mothers almost completely eliminates mother-to-child transmission.  However, a direct study of antiretroviral treatment’s effect on sexual transmission of HIV has not been performed.   Out of the 3,381 couples the group analyzed, 349 of the HIV positive partners started ART during the study.  Only one of the 103 cases of HIV transmission during the study originated from a partner on ART, which translated to a 92 percent reduction in disease transmission.

These results indicate that ART may be a powerful public health tool for use in HIV prevention as well as treatment.

Donnell D, Baeten JM, Kiarie J, Thomas KK, Stevens W, Cohen CR, McIntyre J, Lingappa JR, Celum C; Partners in Prevention HSV/HIV Transmission Study Team.   Heterosexual HIV-1 transmission after initiation of antiretroviral therapy: a prospective cohort analysis.  Lancet. 2010 Jun 12;375(9731):2092-8.