Sexual Partner Types and Incident HIV Infection Among Rural South African Adolescent Girls and Young Women Enrolled in HPTN 068: A Latent Class Analysis

Abstract

Background: Sexual partners are the primary source of incident HIV infection among adolescent girls and young women (AGYW) in sub-Saharan Africa. Identifying partner types at greatest risk of HIV transmission could guide the design of tailored HIV prevention interventions.

Methods: We conducted a secondary analysis of data from AGYW (aged 13-23 years) enrolled in a randomized controlled trial of cash transfers for HIV prevention in South Africa. Annually, AGYW reported behavioral and demographic characteristics of their 3 most recent sexual partners, categorized each partner using prespecified labels, and received HIV testing. We used latent class analysis (LCA) to identify partner types from reported characteristics, and generalized estimating equations to estimate the relationship between both LCA-identified and prespecified partner types and incident HIV infection.

Results: Across 2140 AGYW visits, 1034 AGYW made 2968 partner reports and 63 AGYW acquired HIV infection. We identified 5 LCA partner types, which we named monogamous HIV-negative peer partner; one-time protected in-school peer partner; out-of-school older partner; anonymous out-of-school peer partner; and cohabiting with children in-school peer partner. Compared to AGYW with only monogamous HIV-negative peer partners, AGYW with out-of-school older partners had 2.56 times the annual risk of HIV infection (95% confidence interval: 1.23 to 5.33), whereas AGYW with anonymous out-of-school peer partners had 1.72 times the risk (95% confidence interval: 0.82 to 3.59). Prespecified partner types were not associated with incident HIV.

Conclusion: By identifying meaningful combinations of partner characteristics and predicting the corresponding risk of HIV acquisition among AGYW, LCA-identified partner types may provide new insights for the design of tailored HIV prevention interventions.

Figure 1.

Comparison of sexual partner types identified by latent class analysis (LCA) versus pre-specified partner labels among sexually active adolescent girls and young women (AGYW) ages 13–23 in rural South Africa, from March 2011 to March 2015 (N=2968 partner-reports)^a,b,c a AGYW could report up to 3 sexual partners at each study visit and may have multiple observations due to repeated visits. Sexual partner frequencies include all sexual partners across all follow-up visits. The same partner could be reported at multiple study visits; thus frequencies represent partner-reports, not distinct sexual partners. b Pre-specified partner label missing for 7 partners. c Figure excludes proportions less than 2% (0.57% of Monogamous HIV-Negative Peer Partners; 0.34% of One-Time Protected In-School Peer Partners; 0.97% of Out-Of-School Older Partners; 0.53% of Anonymous Out-of-School Peer Partners; and 1.68% of Cohabiting with Children In-School Peer Partners were categorized as sex work clients).