Objectives:
HIV-1 heterosexual transmission among individuals on antiretroviral treatment (ART) with undetectable viremia is extremely rare. The aim of this study was to evaluate the risk of sexual HIV-1 transmission and other sexually transmitted infections (STIs) in HIV-1 serodifferent couples while the index partner is on ART.
Methods:
HIV transmission was evaluated in 200 HIV-1 heterosexual serodifferent couples in a stable relationship (≥3 months). All HIV-positive individuals had been on ART for ≥3 months and had been followed up for a median preceding time of 4.5 years (range 0.3–16years) at the HIV couples clinic at Hospital Nossa Senhora da Conceição in Porto Alegre, Brazil. Following written informed consent, participants responded to demographic/behavioral questionnaires. Quantitative PCR for HIV RNA, T-cell subsets, and STI testing (syphilis, herpes, human papillomavirus, gonorrhea, and bacterial vaginosis) were performed. Self-collected vaginal swabs were obtained for quantitative HIV genital viral load testing.
Results:
Among 200 couples, 70% of index partners were female. Five seroconversions were observed; the HIV infection incidence was 2.5% (95% confidence interval 0.8% to 5.7%). Mean plasma viral load results were higher in HIV transmitters compared to non-transmitters (p = 0.02). The presence of STIs was significantly greater in couples who seroconverted (60.0% vs. 13.3%; odds ratio 9.75, 95% confidence interval 1.55–61.2; p = 0.023). The duration of undetectable HIV viremia and presence of STIs were associated with HIV transmission.
Conclusions:
Undetectable viremia was the main factor associated with non-transmissibility of HIV in this setting.
Heterosexual transmission occurred more frequently from HIV-infected males to females (rate ratio 3.5; CI, 95% 0.8-16.5 P = 0.259), although without statistical significance, probably because of the small sample. Transmitters showed significantly higher median viral loads (P = 0.042) suggesting that heterosexual transmission of HIV is more a function of viral load than gender of index case. ARV use may play a role in the prevention of HIV-1 heterosexual transmission. Other factors may be involved and should be further evaluated in larger cohorts.
Pregnant women have a significantly higher risk of HIV acquisition during gestation than their non-pregnant counterparts due to behavioral and biological factors. Acute seroconversion during gestation results in increased HIV mother-to-child transmission rates and has been identified as a major public health challenge. In order to address potential HIV seroconversion in our pregnant patients, we conducted a prospective cohort study to evaluate the acceptability of offering HIV testing to sexual partners of HIV-negative pregnant women receiving antenatal care at 2 hospitals in Porto Alegre, Brazil. Over a 14 month study period, HIV-negative pregnant women at two hospital-based clinic sites were encouraged to bring their stable sexual partner for HIV voluntary counseling and testing during prenatal care. Women were re-interviewed following delivery to measure success of the intervention. Of the 1223 HIV-negative pregnant women enrolled in the study, 663 (54%) of their male sexual partners received HIV testing during antenatal care and 4 (0.6%) were diagnosed with HIV infection. Six hundred and forty five women were interviewed at the time of delivery, with 620 (97%) confirming that HIV testing was suggested to their partner. The most common reason provided by women as to why partners did not come for testing was work (69%) and lack of perceived risk (14%). Independent predictors of successful partner testing included being white (OR 1.59, 95% CI 1.18–2.12), married (OR 1.78, 95% CI 1.08–2.94), having an older age of sexual debut (OR 0.94, 95% CI 0.9–0.98), and being recruited at Hospital Conceiçao (OR 2.1, 95% CI 1.52–2.88). We conclude that HIV partner testing during prenatal care is acceptable, rendering this intervention attractive to public health programs targeting prevention of sexually transmitted infections.
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