Background:  There is little rigorous evidence on the ability of behavior change interventions to reduce the incidence of HIV, other sexually transmitted infections (STI), and unplanned pregnancies in young people. We measured the long-term (8-year) impact of the MEMA kwa Vijana adolescent sexual and reproductive health (SRH) intervention on rates of HIV, other STI, SRH knowledge, attitudes, and reported behaviors within a rigorous community randomized controlled trial.

Methods: Since January 99, in rural Tanzania, a package of adolescent SRH interventions (teacher-led, in-school SRH education; youth-friendly health services; community activities; and youth condom promotion and distribution [2000 to 2002 only]) have been implemented in 10 randomly chosen intervention communities, with 10 similar communities acting as a comparison group. Process evaluation in 1999 to 2002 showed high quality and coverage of the intervention. From May 2007 to July 2008, 13,814 young people aged 17 to 27 years from these 20 communities were surveyed. Predefined primary outcomes were HIV and HSV-2 prevalence. Secondary outcomes included other biomedical, behavioral, attitudinal, and knowledge outcomes. Analysis, carried out separately for each sex, was adjusted for community risk stratum, age group and ethnic group.

Results:  Overall prevalence of HIV and HSV-2 was 1.8% and 25.9% in males and 4.0% and 41.4% in females. The intervention did not significantly reduce risk of HIV (males RR 0.91, 95%CI 0.50 to 1.65; females RR 1.07, 0.68 to 1.67) or HSV-2 (males RR 0.94, 0.77 to 1.15; females RR 0.96, 0.87 to 1.07)). The intervention led to a significant reduction in males reporting a high number (>4) of lifetime sexual partners (RR 0.87, 95%CI 0.77 to 0.98) and a significant increase in the number of females reporting use of a condom at last sex with a non-regular partner (RR 1.34, 1.07 to 1.69). There was a clear and consistent beneficial effect on knowledge (RR range 1.11 to 1.24), but no consistent impact on reported attitudes to sexual risk, reported pregnancies nor other reported sexual behaviors.

Conclusions:  This trial, the first to measure the long-term impact on HIV of a behavior change intervention among adolescents, has shown that SRH knowledge can be improved and retained in the long-term, but the interventions had little effect on reported risk behavior and did not reduce HIV or other STI. Future interventions should be accompanied by more intensive efforts to change population norms rather than only focusing the interventions on young people.