Abstract
BACKGROUND: Adolescent girls and young women (AGYW) aged 15-24 years have among the highest risk for HIV and other sexually transmitted infections (STI) across sub-Saharan Africa. A latent class analysis (LCA) was conducted to identify intersecting social- and structural-level determinants of HIV/STI acquisition among AGYW in Ethiopia. METHODS: AGYW were recruited from venues using time-location sampling, completing an interviewer-administered behavioral survey and biological testing for HIV, syphilis, and chlamydia. LCA was used to identify distinct groups, defined by social- and structural-level determinants of HIV/STI risk, among AGYW. Prevalence ratios (PR) and 95% confidence intervals (CI) compared differences in HIV/STI prevalence by group. RESULTS: A total of 1,501 AGYW were enrolled across Addis Ababa (March-May 2018) and Gambella (June-July 2019). We identified three patterns of vulnerability defined by schooling status, migration history, food insecurity, orphan status, social support, and employment. We labeled these groups as "highly vulnerable" (representing ~21% of the population), "stable, out-of-school, migrated" (~42%), and "stable, in-school, never migrated" (~37%). STI prevalence was nearly two-fold higher among AGYW in the "highly vulnerable" group compared to AGYW in the "stable, in-school, never migrated" group (PR 1.93; 95% CI 1.33, 2.80). CONCLUSIONS: Characterizing patterns of vulnerability among AGYW that reflect higher-level social and structural factors can help facilitate early identification of AGYW at the highest risk of HIV/STI acquisition, thus differentiating groups of AGYW who may most benefit from targeted HIV prevention interventions during adolescence and early adulthood.