The effects of the integration of an economic strengthening and HIV prevention education programme on the prevalence of sexually transmitted infections and savings behaviours among adolescents: a full-factorial randomised controlled trial in South Africa

BackgroundMultisectoral approaches are thought necessary to prevent HIV among adolescents. We examined whether an economic strengthening (ES) and an HIV-prevention education intervention improved outcomes when combined versus separately.MethodsWe conducted a full-factorial randomised controlled study to randomise participants into all possible intervention groups based on the two interventions: economic strengthening only (ES-only), HIV-prevention only (HIV-only), both interventions combined (ES+HIV) and no intervention (control). We measured sexually transmitted infections (STIs), self-reported economic and sexual behaviours/knowledge, and pregnancy at a pre-intervention and two post-intervention assessments. Eligible participants were adolescents 14 to 17 years old from a programme supporting vulnerable families in Gauteng Province, South Africa. We estimated intervention effects using repeated measures, generalised linear mixed models.ResultsA total of 1773 adolescents participated (57% female). ES+HIV adolescents had the lowest STI prevalence at first endline; however, the comparison with the control was not significant (OR 0.62, 95% CI 0.27 to 1.41). ES-only or HIV-only groups were not significantly better than the control on STI prevalence (OR 1.53, 95% CI 0.73 to 3.20 and OR 1.47, 95% CI 0.69 to 3.12, respectively). STI prevalence became more similar among the groups at second endline.ES-only adolescents were more likely to participate in savings groups (p=0.004) and plan to save for education (p=0.001) versus the control. ES+HIV adolescents were more likely to plan to save for education versus the control (p=0.001) and HIV-only groups (p=0.002) but did not differ significantly from the ES-only group (p=0.803). The ES+HIV intervention’s effect on HIV knowledge was significant compared with the control (p=0.03) and ES-only groups (p<0.001), but not when compared with the HIV-only group (p=0.091). Effects on pregnancy, sexual behaviours or other economic behaviours were not significant.ConclusionsWe could not confirm the ES and HIV interventions, separately or combined, were effective to reduce STI prevalence. Evaluations of multicomponent interventions should use full-factorial designs to fully assess effects.Trial registration numberNCT02888678