Correcting misperceived norms: An integrated intervention to prevent adolescent sexual violence and HIV in South Africa.

South Africa is a critical hotspot in the global fight against sexual violence and HIV. We report on the development of Schools Championing Safe South Africa, a behavioural intervention that engages adolescent boys and their peers to identify and address misperceived norms related to these epidemics within the school setting. A social norms survey conducted among 1,431 students aged 13-19 at 3 high schools guided the development of intervention content. The survey captured self-reported and perceived peer sexual violence and HIV norms and behaviours. Analyses identified major misalignment (>20%) between perceived peer behaviours/norms and actual behaviours/norms. Perpetration of unwanted sexual petting, oral, vaginal, and anal sex was high: 61%, 53%, 53%, and 44% among boys, and 42%, 26%, 20%, and 18% among girls. We identified underestimation of peer support for bystander intervention, overestimation of peer acceptance of gender-based violence, and underestimation of the extent to which peers would believe a survivor. No misalignment between self and peer HIV risk behaviours were identified. Gaps between actual and perceived behaviours/norms are important targets to correct in a behavioural intervention. Given the interconnected risk factors associated with sexual violence and HIV, addressing them together presents a crucial opportunity to maximize prevention efforts.