Who is sexually active? Using a multi-component sexual activity profile (MSAP) to explore, identify and describe sexually-active high-school students in rural KwaZulu-Natal, South Africa

Background Understanding sexual activity is necessary to prevent sexually transmitted infections. Evidence from Sub-Saharan Africa suggests that 10–20% of youth aged 15–24 are sexually active before reaching 15 years, yet estimating sexual activity remains challenging. This study explored the use of multiple sexual health outcomes to identify sexually-active young women in rural KwaZulu-Natal, South Africa. Methods Using a multi-component sexual activity profile (MSAP), we aimed to identify sexually active students. Based on data from 2675 grade 9 and 10 students attending 14 high schools) in rural KwaZulu-Natal, we constructed a descriptive diagram identifying students who were sexually active by self-report vs MSAP profile. T-tests for two independent samples was performed to compare by sex and ecological variables that characterise students newly-identified as sexually active. Results Using self-report only, 40.3% self-reported as sexually active, whilst the MSAP identified 48.7% (223 additional students). More females were identified than males. Younger adolescents were more likely to underreport sexual activity but were identified using MSAP. Newly-identified as sexually active were more likely to be female ( p = < 0.000), 15 years old or younger ( p = 0.008), less likely to perceive being at risk ( p = 0.037) or have ever used alcohol ( p = < 0.000). At a relational level, they were less likely to report having ever had a boyfriend/girlfriend ( p = 0.000) or to have felt pressured to have sex by their peers ( p = < 0.000) or partners ( p = 0.008). At a familial level they more likely to be of medium socioeconomic (SES) status ( p = 0.037) whilst at a school and community level they were less likely to have repeated a grade ( p = 0.024) and were more likely to be engaged in social activities ( p = 0.032). Conclusions The MSAP profile identified more potentially sexually active students, and gave insight into the characteristics of students who may be unwilling to self-report sexual activity Future work should investigate how this approach could enhance and describe sexually-active adolescents for research and healthcare provision.