Sexual behavior and HIV transmission risk of Ugandan adults taking antiretroviral therapy: 3 year follow-up

Background: Long-term impact of antiretroviral therapy (ART) on sexual HIV-transmission risk in Africa is unknown. We assessed sexual behavior changes and estimated HIV transmission from HIV-infected adults on ART in Uganda. Methods: Between 2003 and 2007, we enrolled and followed ART-naive HIV-infected adults in a home-based AIDS program with annual counseling and testing for cohabitating partners, participant transmission risk-reduction plans, condom distribution and prevention support for cohabitating discordant couples. We assessed participants' HIV plasma viral load and partner-specific sexual behaviors. We defined risky sex as intercourse with inconsistent/no condom use with HIV-negative or unknown serostatus partners in previous 3 months. We compared rates using Poisson regression models, estimated transmission risk using established viral load-specific transmission estimates, and documented sero-conversion rates among HIV-discordant couples. Results: Of 928 participants, 755 (81%) had 36 months data: 94 (10%) died and 79 (9%) missing data. Sexual activity increased from 28% (baseline) to 41% [36 months (P<0.001)]. Of sexually active participants, 22% reported risky sex at baseline, 8% at 6 months (P<0.001), and 14% at 36 months (P = 0.018). Median viral load among those reporting risky sex was 122 500 [interquartile range (IQR) 45 100-353 000] copies/ml pre-ART at baseline and undetectable at follow-up. One sero-conversion occurred among 62 cohabitating sero-discordant partners (0.5 sero-conversions/100 person-years). At 36 months, consistent condom use was 74% with discordant partners, 55% with unknown and 46% with concordant partners. Estimated HIV transmission risk reduced 91%, from 47.3 to 4.2/1000 person-years. Conclusions: Despite increased sexual activity among HIV-infected Ugandans over 3 years on ART, risky sex and estimated risk of HIV transmission remained lower than baseline levels. Integrated prevention programs could reduce HIV transmission in Africa. (C) 2011 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins