02/19/10

PRN Report from 17th CROI:  ART and HIV-Transmission

Limited observational studies indicate that antiretroviral therapy (ART) is associated with decreased risk of HIV transmission, likely through reduced plasma and genital HIV levels. At CROI 2010 in San Francisco Dr. Deborah Donnell presented data from the Partners in Prevention HSV/HIV Transmission study regarding the effect of initiation of ART on transmission of HIV in serodiscordant heterosexual couples.

In this subset analysis of the larger Partners in Prevention study, 349 HIV-infected partners initiated ART. Sexual practices were evaluated for up to 24 months with HIV testing of the uninfected partner every 3 months. Study participants reported unprotected sexual encounters at a rate of 7% throughout the study period. CD4 counts at the time of initiation of ART were <200 cells/mm3 in 52%, between 200 and 349 cells/mm3 in 33%, and > 350 cells/mm3 in 15% of the entrants. None of the participants in the study met criteria for initiation of ART at enrollment, and ART was initiated in seropositive partners during follow-up according to national guidelines.

During the period of evaluation, 102 linked HIV transmissions were found when no ART was prescribed to the HIV-infected partner, while only 1 linked transmission was noted following the initiation of ART in the HIV-infected partner. Higher rates of HIV transmission in the no-ART group were noted in patients with lower CD4 cell counts. Of note, the 1 linked transmission in the ART group was noted in a couple where the HIV-infected partner had initiated ART only 18 days prior to the seroconversion of the uninfected partner. This large prospective study demonstrates that ART use is associated with substantially lower risk for HIV transmission among heterosexual, African, HIV serodiscordant couples where the HIV-infected partner did not meet criteria for ART initiation at enrollment., but later initiated ART according to existing guidelines. Additionally, this data suggested that patients with lower CD4 counts were more likely to transmit virus to non-infected partners. Both of these finding would suggest initiation of ART sooner in serodiscordant couples.

Reference:
Deborah Donnell et al. ART and Risk of Heterosexual HIV-1 Transmission in HIV-1 Serodiscordant African Couples: A Multinational Prospective Study. Presented at 17th Conference on Retroviruses and Opportunistic Infections; San Francisco, CA. Oral Abstract 136.

Source: Reporting from San Francisco for PRN News: A.C. Demidont, DO and Susan Weiss, FNP