Predictors of secondary HIV transmission risk in a cohort of adolescents living with HIV in South Africa

Preventing secondary HIV transmission from adolescents and young people living with HIV (AYPLHIV) to their partners and children is critical to interrupting the HIV infection cycle in sub-Saharan Africa. We investigated predictors of secondary HIV transmission risk (past-year sexual risk combined with past-year viremia) among AYPLHIV in South Africa. DESIGN: A prospective cohort of AYLPHIV in South Africa recruited n = 1046 participants in 2014–2015, 93.6% of whom were followed up in 2016–2017 (1.5% mortality). Questionnaires used validated scales where available and biomarkers were extracted from n = 67 health facilities. METHODS: Multivariate logistic regressions tested baseline factors associated with secondary HIV transmission risk, controlling for covariates, with marginal effect modelling combinations. RESULTS: About 14.2% of AYPLHIV reported high secondary HIV transmission risk. High-risk AYPLHIV were more likely to be sexually infected [adjusted odds ratio (aOR) 2.79, 95% confidence interval (95% CI) 1.66–4.68, P < 0.001], and report hunger (aOR 1.93, 95% CI 1.18–3.14, P = 0.008) and substance use (aOR 2.19, 95% CI 1.19–4.02, P = 0.012). They were more likely to be in power-inequitable relationships (aOR 1.77, 95% CI 1.08–2.92, P = 0.025) and be parents (aOR 4.30, 95% CI 2.16–8.57, P < 0.001). Adolescents reporting none of these factors had a 4% probability of secondary transmission risk, rising to 89% probability with all five identified factors. Older age and early sexual debut were also strongly associated with a higher risk of secondary HIV transmission. CONCLUSION: It is essential to identify and support AYPLHIV at a high risk of secondary transmission. Screening for factors such as mode of infection and parenthood during routine healthcare visits could help identify and provide resources to the most at-risk adolescents.