Moderation and Mediation of an Effective HIV Risk-Reduction Intervention for South African Adolescents

BACKGROUND: "Let Us Protect Our Future" is a sexual risk-reduction intervention for sixth-grade adolescents in South Africa. Tested in a cluster-randomized controlled trial, the intervention significantly reduced self-reported intercourse and unprotected intercourse during a 12-month follow-up period. PURPOSE: The present analyses were conducted to identify moderators of the intervention's efficacy as well as, which theory-based variables mediated the intervention's effects. METHODS: Intervention efficacy over the 3-, 6-, and 12-month follow-up was tested using generalized estimating equation models. RESULTS: Living with their father in the home, parental strictness, and religiosity moderated the efficacy of the intervention in reducing unprotected intercourse. Self-efficacy to avoid risky situations and expected parental disapproval of their having intercourse, derived from Social Cognitive Theory, significantly mediated the intervention's effect on abstinence. CONCLUSIONS: This is the first study to demonstrate that Social Cognitive variables mediate the efficacy of a sexual risk-reduction intervention among South African adolescents.