Adolescent girls and young women [adolescent girls’ and young women’s (AGYW)] aged 15–24 years are disproportionately impacted by HIV, accounting for almost 60% of new cases in their age group worldwide and a staggering 90% of new HIV diagnoses among 15- to 19-year-olds in East and Southern Africa (ESA).¹ While the scale-up of combination HIV prevention has mitigated HIV transmission at the population level, HIV incidence declines have been geographically imbalanced; in countries with generalized HIV epidemics in ESA, new HIV diagnoses have declined by over 30% in the last decade, but in West and Central Africa (WCA), HIV incidence plateaued in 2010 and has since stagnated.^1,2 Compared with ESA, WCA’s HIV epidemic is distinguished by lower (but moderate) HIV prevalence (1.3%); higher HIV-associated mortality (20 deaths per 100,000 population), attributed primarily to sub-optimal coverage of HIV care and treatment services—with nearly a quarter of persons living with HIV not receiving antiretroviral therapy; and performance gaps in HIV epidemic control efforts, especially for girls and women.^1,3 Despite a more concentrated HIV epidemic in WCA, 1 in 5 new HIV diagnoses in the region are observed in AGYW (aged 15–24 years)—comparable with the incidence disparities documented in ESA.^1,2

Numerous studies have identified sociostructural vulnerabilities (eg, gender-inequitable norms and relationships, food insecurity, school attrition) as factors associated with behaviors (eg, transactional sex, diminished capacity to safely negotiate condom use, coercive sex) that heighten AGYW’s susceptibility to HIV acquisition.^4–8 Most evidence related to heightened HIV vulnerability among AGYW has emanated from generalized HIV epidemic contexts in ESA, where HIV burdens among women are substantially larger than in WCA.² Moreover, existing scholarship has emphasized the contribution of AGYW’s embodied vulnerability (ie, risk experienced at the individual level) to HIV acquisition but has been less attentive to partner-level (eg, male partner occupation and knowledge of HIV status, shared decision-making, and autonomy in sexual relationships) and sexual network (eg, number of extramarital sexual contacts among AGYW’s male partners) characteristics that critically potentiate the HIV risk environment for AGYW.^9,10 There is a critical dearth of this scholarship specifically in WCA, where—despite unmet HIV prevention needs among AGYW—virtually no studies have described relationship characteristics potentially contributing to HIV transmission dynamics among AGYW and their male partners, especially at the population level.

Given the distinct profile and trajectory of WCA’s HIV epidemic, understanding contextually specific partner-level factors associated with HIV seropositivity among AGYW is vital to identifying prevention needs and informing tailored programming to AGYW and their male partners in the region. Accordingly, we pooled population-based HIV-seroprevalence surveys from Cameroon and Côte d’Ivoire to identify sexual relationship typologies and quantify their disparate effects on HIV burdens among sexually active AGYW in WCA.

Overall, 45,412 individuals across countries (Cameroon: N = 27,085; Côte d’Ivoire: N = 18,327) completed a PHIA survey, of whom 12% were sexually active AGYW eligible for inclusion in the present analysis. The final analytic sample included 5523 AGYW (Cameroon: n = 3,200, 47.3%; Côte d’Ivoire: n = 2,323, 52.7%) reporting 6839 unique past-year sexual partners (Table 1). Most AGYW were aged 20–24 years (62%), were unmarried (53%), had secondary-level education or higher (52%), reported no past-year income-based employment (70%), and lived in urban areas (58%). More than half (52%) had had a live birth, and 14% reported being pregnant at the time of survey. Fewer AGYW reported first sex before age 15 (15%), having ≥2 past-year sexual partners (15%), and condom use at last sex (28%). AGYW reported an average of 1.22 past-year sexual partners (95% CI: 1.19 to 1.24), which was significantly (P < 0.001) higher in Côte d’Ivoire (mean: 1.30, 95% CI: 1.25 to 1.35) than in Cameroon (mean: 1.13, 95% CI: 1.11 to 1.15). Fewer than two-thirds of sexually active AGYW reported ever testing for HIV (60%). The pooled HIV prevalence was 1.9% (95% CI: 1.4% to 2.4%)—significantly (P = 0.010) higher in Cameroon (2.7%, 95% CI: 1.9% to 3.4%) than in Côte d’Ivoire (1.2%, 95% CI: 0.5% to 1.8%).

Four distinct sexual partnership types emerged from LCA (AIC: 39,868.558; BIC: 40,051.141; entropy: 0.612; χ² LRT: 49.580, P = 0.0522; VLMR LRT: 52.116, P = 0.0745) and were characterized as follows (Fig. 1): Type 1 (~46% class prevalence), characterized by primarily cohabiting (~75%), age-disparate (~80%) partnerships; Type 2 (~15% class prevalence), distinguished by relationships that were non-cohabiting (~96%) with similarly aged (~95%) male partners; Type 3 (~30% class prevalence), characterized by primarily one-off (~52%), age-disparate (~74%) partner-ships; and Type 4 (~9% class prevalence), distinguished by partnerships that were non-cohabiting (~77%), steady/permanent (~98%), age-disparate (~71%), and unknown HIV serostatus of partners (~0%).

In multivariable mixture modeling, AGYW reporting one-off, age-disparate partners [Type 3] exhibited significantly elevated odds of HIV seropositivity related to AGYW reporting cohabiting, age-disparate partners [Type 1] [adjusted odds ratio (adjOR) = 2.28, 95% CI: 1.96 to 2.61, P = 0.001] and non-cohabiting, similar-aged partners [Type 2] (adjOR = 7.46, 95% CI: 6.86 to 8.06, P = 0.005), respectively. Similarly, AGYW with non-cohabiting, permanent, age-disparate partners [Type 4] exhibited significantly higher elevated odds of HIV seropositivity relative to AGYW with cohabiting, age-disparate partners [Type 1] (adjOR = 2.05, 95% CI: 1.64 to 2.46, P = 0.014) and non-cohabiting, similar-aged partners [Type 2] (adjOR = 6.71, 95% CI: 6.09 to 7.33, P = 0.007), respectively.

LCA uncovered 4 sexual relationship types among AGYW in Cameroon and Côte d’Ivoire, revealing heterogeneities in partnership characteristics that may confer differential HIV acquisition risks, with implications for programming. AGYW with one-off, age-disparate [Type 3] and non-cohabiting, permanent, age-disparate [Type 4] partnerships were more likely to be living with HIV. We found that relationship permanence or fluidity, partner residence (cohabiting or non-cohabiting), and male partner age were associated with AGYW’s HIV status synergistically, rather than independently, as emphasized in the extant scholarship from ESA.^10,17,18 Upstream socio-structural (eg, economically motivated sexual activity, condom use coercion, non-disclosure of HIV status between partners) and epidemiologic forces (eg, high-density sexual networks among male partners) likely contribute to disparities in HIV burdens among latent partnership profiles emerging from LCA.^2,7,10 Moreover, unlike prior studies from ESA,^17–19 AGYW in Cameroon and Côte d’Ivoire reported age-disparate, cohabiting partners with greater frequency—likely a reflection of marriage or cohabiting-union formation at younger ages among AGYW in WCA.²⁰ Consistent with extant scholarship,^4,19 transactional sex also appeared to cluster in latent partnership profiles exhibiting the highest HIV burdens—reaffirming the potential contribution of exchange sex to elevated HIV acquisition risks in AGYW. HIV risk assessments and risk counseling should, therefore, consider the contributions of non-cohabiting, older male partners (both permanent and non-permanent), as well as transactional sex relationships, to AGYW’s HIV acquisition risks in Cameroon and Côte d’Ivoire.

This is among the first population-based studies to characterize sexual relationship typologies among AGYW in WCA and quantify their discrete associations with HIV seropositivity. LCA uncovered heterogeneous sexual partner-ship types—and the clustering of HIV seropositivity among them—reported by AGYW in Cameroon and Côte d’Ivoire. An expanding menu of HIV prevention tools, namely long-acting injectable pre-exposure prophylaxis, and diagnostic technologies like HIV self-testing should be availed to AGYW in transactional sex relationships with older, nonpermanent partners in high-transmission localities across WCA.