The effectiveness and cost-effectiveness of behavioural interventions for the prevention of sexually transmitted infections in young people aged 13-19: a systematic review and economic evaluation

To assess the effectiveness and cost-effectiveness of schools-based skills-building behavioural interventions to encourage young people to adopt and maintain safer sexual behaviour and to prevent them from acquiring sexually transmitted infections (STIs). Electronic bibliographic databases (e.g. MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations, EMBASE, CINAHL, PsycINFO, CCRCT, NHS EED and DARE) were searched for the period 1985 to March 2008. Bibliographies of systematic reviews and related papers were screened and experts contacted to identify additional published and unpublished references. A systematic review of effectiveness and economic evaluation of cost-effectiveness were carried out. A descriptive map of studies that met inclusion criteria was produced, and keywords were developed and systematically applied to these studies to identify a policy-relevant subset of studies for the systematic review. Outcome data for variables including sexual behaviour were extracted. An economic model was developed to compare the costs and consequences of the behavioural interventions. A Bernoulli statistical model was constructed to describe the probability of STI infection. There were few significant differences between the interventions and comparators in terms of changes in sexual behaviour outcomes, although there were some significant differences for knowledge and some measures of self-efficacy. The studies included in this review conducted relatively short follow-up assessments at a time when many young people were becoming sexually active. It is therefore possible that favourable behaviour change may have occurred, and become more cost-effective, with time, as sexual activity becomes more routine in young people's lives. The quality of the intervention provider influenced whether or not young people found the interventions to be acceptable and engaging; enthusiasm and considerable expertise were important for effective class management and delivery of skills-building activities, and a supportive school culture was also helpful. Recognition of young people's individual needs in relation to sexual health was another important factor. No conclusions could be drawn on the impact of the interventions on sexual health inequalities due to a lack of relevant data on socioeconomic status, gender and ethnicity. The results of the economic evaluation were considered to be illustrative, mainly due to the uncertainty of the effect of intervention on behavioural