Transactional sex and age-disparate sexual partnerships among adolescent girls and young women in Tanzania

Adolescent girls and young women (AGYW) continue to experience a high incidence of HIV in southern and eastern Africa, even in the context of large-scale HIV prevention interventions. In Tanzania, AGYW account for the largest proportion of new infections and have a higher risk of HIV acquisition than males of comparable age. We used routinely collected data from the PEPFAR/USAID-funded Sauti Project, a large combination HIV prevention program, to examine the relationship between transactional sex and sex with older partners among AGYW in Tanzania (2015-2020). Out-of-school AGYW 15-24 years completed a vulnerability index and were tested for HIV. We estimated weighted prevalence ratios (PR) and 95% confidence intervals (CI) for the associations of transactional sex (sex exchanged for money/services/gifts outside of sex work) and sex with older partners (≥5-years older, ≥10-years older) with prevalent HIV. We assessed potential synergism between exposures, and subgroup analyses explored associations among girls 15-19. 67,357 AGYW completed the vulnerability index and 14,873 had captured HIV testing records. Median age was 20 years (IQR 18-22). Transactional sex and age-disparate sex were common (35% and 28%, respectively); 13% of AGYW reported both behaviors. HIV prevalence was associated with both transactional sex (PR:1.28; 95% CI 1.00-1.63) and age-disparate sex (PR:1.26, 95% CI 0.99-1.60). In common referent analysis, transactional sex remained strongly associated with HIV, even in the absence of age-disparate sex (PR 1.41; 95% CI 1.02-1.94). Evidence of statistical synergism was not present, suggesting both transactional sex and age-disparate sex operate through similar pathways to increase HIV risk. Increased specificity within HIV prevention programs is needed to better meet the sexual and reproductive health needs of AGYW at high risk of HIV in Tanzania, including investment in tailored youth-friendly strategies for AGYW who have been marginalized from the current HIV response. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement KR was supported by an award from the National Institute of Mental Health (K01MH129226). KA was supported by two awards from the National Institute of Mental Health (R25MH083620, F31MH124583). SB was supported by an award from the National Institute of Allergy and Infectious Diseases (R01AI170249). SS was also supported by an award from the National Institute of Allergy and Infectious Diseases (P30AI094189, Sub-Project ID 9272). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Not Applicable The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethical approval for the use of de-identified routine data was provided by the National Institute for Medical Research (NIMR/HQ/R.8c/Vol.1/678) and the Johns Hopkins Institutional Review Board (IRB No. 00006673). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Not Applicable I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Not Applicable I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Not Applicable Data may be made available by the corresponding author upon receipt of reasonable request.