Perceived efficacy of HIV treatment-as-prevention among university students in Johannesburg, South Africa.

OBJECTIVE: Antiretroviral therapy (ART) nearly eliminates HIV transmission. Yet information on treatment as prevention (TasP) has been slow to diffuse in sub-Saharan Africa. We assessed TasP knowledge among university students in South Africa. METHODS: We conducted a cross-sectional survey of first-year university students at a large public university in Johannesburg, South Africa, all of whom would have recently completed secondary school HIV curricula. Respondents were asked to consider the likelihood of HIV transmission in a serodiscordant couple having condomless sex with and without virally suppressive ART. Beliefs were elicited using a 0-20 visual scale. Perceived TasP efficacy was computed as the relative reduction in risk associated with virally suppressive ART. We compared beliefs with estimates from the scientific literature and assessed associations with demographics, HIV testing history and qualitative measures of HIV knowledge and risk perception. RESULTS: The analysis included 365 university students ages 18-25 years (48% female, 56% from Gauteng Province). On average, perceived annual risk of HIV transmission with virally suppressive ART was 73%; the objective risk is <1%. On average, respondents perceived that virally suppressive ART reduced annual transmission risk by 17%; the objective reduction in risk is >96%. We observed no differences in perceived TasP efficacy by participant characteristics and testing history. Perceived TasP efficacy was correlated with the (correct) belief that HIV risk increases with sexual frequency. CONCLUSIONS: University students in South Africa underestimated the prevention benefits of HIV treatment. Low knowledge of TasP could limit demand for HIV testing and treatment among young adults.