Furthermore, the prevalence of first sex vulnerabilities was high across AGYW irrespective of their engagement in SW, TS, or CS, suggesting considerable overlap in early HIV risk across subsets of AGYW in Kenya. Indeed, vulnerabilities in the partnership domain (especially exchange of gifts or money at first sex) were frequent and similar between AGYW who currently engage in SW and TS. Up to 40% of AGYW engaged in CS reported the exchange of gifts or money at first sex. Reasons may include similar economic forces that shape a first sex event, and engagement in SW and TS48 as well as overlapping sexual networks.49 In addition, our data are right-censored: the cross-sectional snapshot of current engagement in SW, TS, or CS means that some women currently engaged in TS or CS may enter formal SW and self-identify as a sex worker later. However, we cannot infer that first sex experiences lead AGYW to frequent SW hotspots or to engage in SW, TS, or CS. Nonetheless, SW hotspots could be practical sites for HIV programmatic outreach and engagement with AGYW who experienced a higher probability of HIV-associated first sex vulnerabilities, and in particular, compared with a broader population of AGYW identified in household surveys.42
Our findings also suggest that experiences at first sex are an early marker of, or may influence, the trajectory of HIV-associated vulnerabilities experienced thereafter. Ours is among the first studies to examine first sex vulnerabilities with ongoing or future experience of GBV.4,43 As in our study, one previous study in Tanzania showed women who experienced a forced first sex event were nearly 6 times more likely to experience repeated sexual or physical violence.46 Indeed, repeated acts of violence perpetrated by more than one partner are commonly reported47,50 suggesting that GBV-associated HIV transmission may be compounded over an AGYW's sexual life course.22
Our findings further support the inclusion of structural interventions including sexual health education, violence reduction, and economic empowerment to women before they become sexually active, and indeed, before achieving menarche. Interventions designed to influence prepubescent and early sexual life course include school-based programs56 and community-wide structural programs focused on addressing gender norms to delay sexual debut and reduce GBV.59–62 More recently, there is a growing focus on integrating sexual and reproductive behavioral and structural interventions (eg, conditional and unconditional cash transfer) within youth friendly health services.63,64 The findings could also be used to help identify AGYW who may be most at risk of ongoing vulnerabilities. In Kenya's Fast Track Plan to End HIV and AIDS Among Adolescents and Young People,3 a core component includes screening AGYW for sexual and reproductive health. Inclusion of first sex screening questions across the 4 domains examined here, with particular focus on vulnerabilities associated with the 2 outcomes we studied (lifetime GBV and HIV prevalence), could help to optimize sexual risk screening and identify those who may be at highest risk of prevalent HIV infection and future HIV risk.
Study limitations include the use of recall data on first sex events, which are subject to measurement bias. Data from repeated-measures studies in sub-Saharan Africa suggest that 30%–56% of self-reported estimates of age at first sex may be unreliable, although the measurement errors did not influence estimates of the median age of first sex.65 The data are also subject to social desirability bias resulting from the personal nature of questions around first sex and our use of face-to-face interviews—leading to potential under-reporting of vulnerabilities. Similarly, our classification of subgroups (SW, TS, and CS) relied on self-reported and disclosed partnership types, which could lead to misclassification of participants. We performed a cross-sectional study and thus cannot infer causation between events at first sex and lifetime GBV or HIV infection. Future work includes additional multivariate analyses to identify overlap in first sex vulnerabilities and potential mediators of HIV prevalence to disentangle the pathways potentially influenced by experiences at first sex, and qualitative studies to better explore the context surrounding experiences leading up to and risk factors for first sex vulnerabilities.66
The authors thank all the women who participated in this study. The authors also acknowledge the efforts of the Transitions Study team and their partners.
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