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 0.3-16 years) 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.

Background

An undetectable serum HIV-1 load is key to effectiveness of antiretroviral (ARV) therapy, which depends on adherence to treatment. We evaluated factors possibly associated with ARV adherence and virologic response in HIV-infected heterosexual individuals.

Methods

A cross-sectional study was conducted in 200 HIV-1 serodiscordant couples and 100 unpartnered individuals receiving ARV treatment at a tertiary hospital in southern Brazil. All subjects provided written informed consent, answered demographic/behavioral questionnaires through audio computer-assisted self-interviews (ACASI), and collected blood and vaginal samples for biological markers and assessment of sexually transmitted infections (STIs). HIV-negative partners were counseled and tested for HIV-1.

Results

The study population mean age was 39.9 years, 53.6% were female, 62.5% were Caucasian, 52.6% had incomplete or complete elementary education, 63.1% resided in Porto Alegre. Demographic, behavioral and biological marker characteristics were similar between couples and single individuals. There was an association between adherence reported on ACASI and an undetectable serum viral load (P<0.0001). Logistic regression analysis demonstrated that single-tablet ARV-regimens were independently associated with adherence (OR = 2.3; 95CI%: 1.2-4.4; P = 0.011) after controlling for age, gender, education, marital status, personal income, ARV regimen, and median time of ARV use. A positive correlation between genital secretion PCR results and serum viral load was significant in the presence of STIs (r = 0.359; P = 0.017). Although HIV PCR detection in vaginal secretions was more frequent in women with detectable viremia (9/51, 17.6%), it was also present in 7 of 157 women with undetectable serum viral loads (4.5%), p = 0.005.

Conclusions

ARV single tablet regimens are associated with adherence. Detectable HIV-1 may be present in the genital secretions of women with undetectable viremia which means there is potential for HIV transmission in adherent individuals with serologic suppression.

HIV-negative individuals in serodiscordant partnerships experience reduced risk of HIV acquisition when their partners adhere to ART and achieve undetectable viral loads. Partnership support may encourage ART adherence, reducing viral load and the risk of HIV transmission. This study aims to determine whether HIV viral suppression is associated with partnership status and partnership support among 201 HIV positive (HIV+ individuals in serodiscordant partnerships and 100 HIV+ unpartnered individuals receiving care at Hospital Nossa Senhora da Conceição in Porto Alegre, Brazil between 2014 and 2016. Clinical data and patient-reported questionnaire data were assessed, and propensity scores were used to control for confounding variables in adjusted logistic regression models. Viral suppression did not significantly differ between HIV+ partnered (78.5% virally suppressed) and unpartnered (76.0% virally suppressed) individuals. Among individuals in partnerships, viral suppression was significantly associated with having a partner who attended monthly clinic visits (AOR 2.99; 95% CI 1.00-8.93). Instrumental social support-attending monthly visits-may improve the odds of viral suppression among HIV+ individuals in serodiscordant relationships.