Introduction Antiretroviral pre-exposure prophylaxis (PrEP) reduces the incidence of acquisition of human immunodeficiency virus type 1 (HIV-1) in men who have sex with men and is a promising approach for preventing HIV-1 in heterosexual populations. Methods We conducted a randomized, three-arm trial of oral antiretroviral PrEP among heterosexual couples from Kenya and Uganda in which one member was HIV-1 seronegative and the other HIV-1 seropositive. Seronegative partners were randomly assigned to once-daily tenofovir (TDF), combination emtricitabine/tenofovir (FTC/TDF), or matching placebo and followed monthly for up to 36 months. At enrollment, HIV-1 seropositive partners were not eligible for antiretroviral therapy under national guidelines. All couples received standard HIV-1 treatment and prevention services, including individual and couples risk-reduction counseling and condoms. Results 4758 couples were enrolled; for 62%, the HIV-1 seronegative partner was male. For HIV-1 seropositive participants, the median CD4 count was 495 cells/μL (interquartile range 375–662). Of 82 post-randomization HIV-1 infections, 17 were among those assigned TDF (incidence 0.65 per 100 person-years), 13 among those assigned FTC/TDF (incidence 0.50 per 100 person-years), and 52 among those assigned placebo (incidence 1.99 per 100 person-years), indicating a 67% relative reduction in HIV-1 incidence for TDF (95% CI 44 to 81, p<0.001) and 75% for FTC/TDF (95% CI 55 to 87, p<0.001). HIV-1 protective effects of FTC/TDF and TDF were not significantly different (p=0.23), and both study medications significantly reduced HIV-1 incidence in both men and women. The rate of serious medical events was similar across the study arms. Conclusions Oral TDF and FTC/TDF provided substantial protection against HIV-1 acquisition in heterosexual men and women, with comparable efficacy of TDF and FTC/TDF. (Funded by the Bill and Melinda Gates Foundation; ClinicalTrials.gov number NCT00557245)

Background-High plasma HIV-1 RNA concentrations are associated with increased risk of HIV-1 transmission. Initiation of antiretroviral therapy (ART) reduces plasma HIV-1 concentrations, but little empiric data are available on the rate of sexual HIV-1 transmission from persons receiving ART.

BACKGROUND Most persons who are infected with human immunodeficiency virus type 1 (HIV-1) are also infected with herpes simplex virus type 2 (HSV-2), which is frequently reactivated and is associated with increased plasma and genital levels of HIV-1. Therapy to suppress HSV-2 reduces the frequency of reactivation of HSV-2 as well as HIV-1 levels, suggesting that suppression of HSV-2 may reduce the risk of transmission of HIV-1. METHODS We conducted a randomized, placebo-controlled trial of suppressive therapy for HSV-2 (acyclovir at a dose of 400 mg orally twice daily) in couples in which only one of the partners was seropositive for HIV-1 (CD4 count, ≥250 cells per cubic millimeter) and that partner was also infected with HSV-2 and was not taking antiretroviral therapy at the time of enrollment. The primary end point was transmission of HIV-1 to the partner who was not initially infected with HIV-1; linkage of transmissions was assessed by means of genetic sequencing of viruses. RESULTS A total of 3408 couples were enrolled at 14 sites in Africa. Of the partners who were infected with HIV-1, 68% were women, and the baseline median CD4 count was 462 cells per cubic millimeter. Of 132 HIV-1 seroconversions that occurred after randomization (an incidence of 2.7 per 100 person-years), 84 were linked within couples by viral sequencing: 41 in the acyclovir group and 43 in the placebo group (hazard ratio with acyclovir, 0.92, 95% confidence interval [CI], 0.60 to 1.41; P = 0.69). Suppression with acyclovir reduced the mean plasma concentration of HIV-1 by 0.25 log10 copies per milliliter (95% CI, 0.22 to 0.29; P<0.001) and the occurrence of HSV-2–positive genital ulcers by 73% (risk ratio, 0.27; 95% CI, 0.20 to 0.36; P<0.001). A total of 92% of the partners infected with HIV-1 and 84% of the partners not infected with HIV-1 remained in the study for 24 months. The level of adherence to the dispensed study drug was 96%. No serious adverse events related to acyclovir were observed. CONCLUSIONS Daily acyclovir therapy did not reduce the risk of transmission of HIV-1, despite a reduction in plasma HIV-1 RNA of 0.25 log10 copies per milliliter and a 73% reduction in the occurrence of genital ulcers due to HSV-2. (ClinicalTrials.gov number, NCT00194519.)

Summary Background Hormonal contraceptives are used widely but their effects on HIV-1 risk are unclear. Methods We followed 3790 heterosexual HIV-1 serodiscordant couples from seven African countries participating in two longitudinal HIV-1 incidence studies. Among hormonal contraceptive users (including injectable and oral contraceptive users) and nonusers, we compared rates of HIV-1 acquisition in women and HIV-1 transmission from women to men. Findings Among 1314 couples in which the HIV-1 seronegative partner was female, HIV-1 acquisition rates were 6.61 and 3.78 per 100 person-years among hormonal contraceptive users and nonusers (adjusted hazard ratio [AHR]=1.98, 95% confidence interval [CI] 1.06–3.68, p=0.03). Among 2476 couples in which the HIV-1 seronegative partner was male, HIV-1 transmission rates from women to men were 2.61 and 1.51 per 100 person-years in those whose partners currently used versus did not use hormonal contraception (AHR=1.97, 95% CI 1.12–3.45, p=0.02). In subgroup analysis, injectable contraceptive users had increased risk for acquiring and transmitting HIV-1 to their partner and HIV-1 seropositive women using injectable contraception had higher genital HIV-1 RNA concentrations, suggesting a mechanism for increased transmission risk. Oral contraceptives were used too infrequently to draw definitive conclusions about HIV-1 risk. Interpretation Women should be counseled about potentially increased risk of HIV-1 acquisition and transmission with hormonal contraception, particularly injectable methods, and about the importance of dual protection with condoms to decrease HIV-1 risk. Non-hormonal or lower-dose hormonal contraceptive methods should be considered for women with or at-risk for HIV-1. Funding National Institutes of Health (R03 HD068143, R01 AI083034, P30 AI027757, and T32 AI007140) and the Bill and Melinda Gates Foundation (26469 and 41185).

We conducted a prospective study among women in Mombasa, Kenya, to determine whether Trichomonas vaginalis infection was associated with an increased risk of human immunodeficiency virus type 1 (HIV-1) infection. At monthly follow-up visits, laboratory screening for HIV-1 and genital tract infections was conducted. Among 1335 HIV-1-seronegative women monitored for a median of 566 days, there were 806 incident T. vaginalis infections (23.6/100 person-years), and 265 women seroconverted to HIV-1 (7.7/100 person-years). Trichomoniasis was associated with a 1.52-fold (95% confidence interval, 1.04-2.24-fold) increased risk of HIV-1 acquisition after adjustment for potential confounding factors. Treatment and prevention of T. vaginalis infection could reduce HIV-1 risk in women.