This review found a paucity of published school-based interventions in sub-Saharan Africa relative to the magnitude of the AIDS epidemic. Participants' socio-demographic characteristics such as age, sex and school grade were generally well reported in our included studies, but socio-economic status and religion were less well reported. Description of socioeconomic status and religious affiliation in future studies could better inform on programme generalisability to other settings.
Justification of sample size and validation of measurement tools were not reported in many studies. Although no studies justified the timing of intervention delivery, conducting the intervention during school hours seemed to give the opportunity for more interaction between researchers and stakeholders in Kuhn et al.
] even though the programme reportedly led to "a disruption in normal school activities". Future studies should address both these preceding aspects of the intervention, and others relating to establishing the context for the particular intervention delivered such as duration and programme monitoring as discussed below.
To enable facilitators to effectively conduct the intervention and its monitoring training should be provided rather than assuming facilitators' knowledge and perceptions on the particular sexual health intervention under evaluation. For example, Klepp et al.
] reported that teachers avoided condom-use messages despite supportive policies being in place at the time of the evaluation, and this was only acknowledged after delivery of the intervention had been concluded. Future studies should be conducted after establishing an appropriate framework, i.e. one informed by both theory and research evidence from systematic reviews, qualitative studies and discrete choice experiments (which may ascertain participants preferences and justify the intervention and components or methods employed in its evaluation). This is recommended for the evaluation of complex interventions [33
], of which prevention HIV/AIDS among adolescents is representative. If training of staff, a theoretical basis and evidence-based interventions had been part of the studies in our systematic review it could have helped explanation why behavioural change has been so difficult to achieve in HIV/AIDS prevention programmes among Sub-Saharan African adolescents.
Tactical communication of the goals of an intervention, to avoid areas or terms that lead to unending debates, is a characteristic that helps in smooth delivery of interventions. In Kuhn et al
] for instance, the intervention was portrayed as 'a means to prevent STD/HIV/AIDS' rather than as 'providing sex education' to stakeholders, making it more acceptable. Such involvement of stakeholders, particularly parents and teachers, very early in the design of the intervention, and exhibiting cultural sensitivity in a community where it had hitherto been a taboo for adults and pupils to discuss sexual issues, could have led to the significant improvement in communication between youths and their parents and teachers [27
]. Fawole et al
] reported that the school principal gave full support to the condom content of the intervention, also following involvement in the intervention design.
Use of multiple media and activities in communication or delivery of messages was employed in almost all studies. More than one facilitator was also used in many studies but we are unable to determine the relative contribution of each medium or facilitator to programme effectiveness within the scope of this review. However, the effectiveness of the different interventions appeared similar across all studies from the overall trend of effectiveness by reported significant change as shown in Table . More focused studies or studies employing factorial designs to vary different programme components could further inform on the strengths and weaknesses of using different media and facilitators in intervention design and delivery.
Skill-based content of interventions involving active participation of students and more lengthy interventions offering the opportunity for repeated exposure to the same theme appeared to be associated with greater effectiveness. This was exemplified by comparing the 'DramAide' intervention by Harvey et al
] which was longer and employed intense involvement of students compared to the 'booklet intervention' control group.
Many studies reported outcomes at immediate post-intervention or short term (≤ six months) follow up. To reduce limitation in the long-term evidence of effect of school-based interventions to prevent STI/HIV in sub-Saharan Africa and to determine if certain outcomes routinely demonstrate a delay effect (e.g. reported change in practicing abstinence did not reach statistical significance until 12 months in Stanton et al
], future studies should be designed to be able to report long-term (≥ one year) outcomes.
Design of future interventions in terms of focus is important. Rusakaniko et al
] which was not very focused in terms of types of schools, content of intervention and outcomes measured reported no significant change, not even in knowledge at the end of the intervention. Conducting more focused interventions could be more informative in making associations to both internal and external validity of a study.
Employing sub-analysis of outcomes based on pre-intervention sexual history as conducted by Stanton et al
] and James et al
] is highly recommended for future research towards the development of interventions that are more tailored to fit specific groups.
Certain attributes of effective sexual health interventions have been described to include having clear and focused outcome behaviour, addressing all social influences relating to the students, including opportunity for practice of communication and negotiation skills, involving students in experiential activities towards personalising relevant information, having their foundation in social learning theories and having their content designed to reinforce group specific values and norms [34
]. The findings of our review are not in contrast with any of these. There was also similarity in the trends for effectiveness of interventions in our included studies, in effecting change in knowledge, attitudes, and behaviour change, when compared to a previous review by Gallant and Maticka-Tyndale [11
]. To summarise the effectiveness of interventions in the population represented within the scope of this review, we found that the most significant changes were reported in knowledge, being followed by changes in attitudes. Outcomes relating to future intentions were next, while the least significant changes were in actual behaviour.
Although our aim was to conduct a focused review with good quality studies that would be valid and generalisable to sub-Saharan Africa, we acknowledge that this review is limited by the possibility of having missed relevant studies within the timescale and resources available. Although we applied no language limitations to our searches, all our studies were conducted and/or reported in English, implying the possibility of having missed relevant studies conducted in non-English speaking African countries. Most of our studies were conducted in Southern Africa and our strict exclusion criteria led to the exclusion of some studies, mostly from Eastern Africa, which might limit the generalisability of our findings to all sub-Saharan Africa.