Antiretroviral therapy (ART)-induced viral suppression has been shown to reduce sexual transmission of HIV. Data for prevention of HIV transmission are strongest for heterosexual transmission. ART does not produce immediate or universal viral suppression, and perception of infectiousness (POI) may impact sexual risk taking. Changes in POI as a result of ART may have implications for transmission and population incidence.
A5257 followed 1809 ART-naïve participants in a randomized open-label ART study for up to 192 weeks(W). Self-report of POI was assessed at baseline and annually via a visual analog scale (0-100). Pre-defined infectiousness categories were high (67-100), medium (34-66), low (1-33), not infectious (0). We evaluated a decline in POI defined as ≥10 unit absolute decrease with a change in POI category at W48 relative to baseline; a decline to not infectious POI was evaluated as a secondary outcome. Multivariable binary Poisson regression was used to evaluate factors associated with these outcomes.
At baseline (pre-ART), 58%, 26%, 10%, 6% participants self-categorized as high, medium, low, or not infectious, respectively. At W48, 38%, 20%, 32%, and 10% self-categorized as high, medium, low, or not-infectious; 91% had HIV RNA<50 c/mL. 49% reported a reduction in POI from baseline to W48. In multivariable analysis, higher baseline POI, younger age and higher education were associated with greater risk of a decline in POI; non-Hispanic Black race and pre-ART CD4<50 cells was associated with lower risk (Figure). Factors associated with a decline to not infectious POI (n=99) were baseline POI, female sex, and absence of stimulant drug use. Associations with RNA suppression were not apparent for either outcome (p=0.94 and 0.87, respectively). Only 8 of 99 participants who perceived themselves as not infectious on ART at W48 had RNA >50 c/mL.
Nearly half of participants reported a reduction in POI 48W after initiating ART. Those who were younger and more educated were more likely to report a reduction in POI, whereas those of black race or with advanced disease were less likely to report a reduction. Overall, relatively few participants perceived themselves non-infectious – a salutary finding for prevention. Interestingly, actual viral suppression was not associated with POI. Understanding how POI changes due to therapy, and how it relates to condomless sex, will be critical for designing interventions to maximize the benefits of treatment as prevention.