Declines in HIV Incidence and Prevalence and Predictors Among Adolescents and Young Adults: An Observational Cohort Study, Rakai, Uganda, 2005-2020.

BACKGROUND

HIV acquisition among adolescents and young adults (AYA, 15-24 years) is influenced by individual factors, community factors, and public policies and programs. We explored the association of HIV incidence and prevalence with these factors over time among AYA in Rakai, Uganda.

METHODS

We examined trends over nine survey rounds (2005-2020) of the Rakai Community Cohort Study (RCCS), an open population-based surveillance cohort of individuals living in 30 continuously followed communities in south-central Uganda (n= 35,938 person rounds). We evaluated the associations between individual and community-level factors including HIV community viremia (CV, a measure of community-level ART use and HIV prevalence) and HIV incidence and prevalence. Logistic GEE, Poisson GLM and univariate models were run for HIV prevalence, HIV incidence, and predictors of interest, respectively.

FINDINGS

HIV incidence and prevalence declined over time after round 14 (2010-2011) by 66% among AYA men and after round 17 (2015-16) by 60% among young women. Between survey round 11 (2007-2008) and round 19 (2017-2019), the proportions reporting being sexually experienced declined from 58% to 38% in adolescent men (15-19) and from 65% to 35% among adolescent women. The prevalence of VMMC among adolescent men increased from 20% in round 11 to 79% in round 19. At the community-level, we found substantial increases in ART use among PLHIV ( 5% in round 11 and 86% in round 19) with corresponding declines in community viremia. In multivariable analyses, a combination of individual and community-level factors were found to predict HIV incidence and prevalence among AYA, notably VMMC among young men and community viremia among young women.

INTERPRETATION

Declines in HIV incidence and prevalence occurred first among AYA men and later among AYA women. These coincided with declines in sexual experience and with public policies that increased access to VMMC and ART. Combination HIV prevention with AYA needs to address risk factors at multiple levels.

FUNDING

This work was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD, grants R01HD091003, RO1HD070769, R01HD050180, R01 HD074949, and P2CHD058486), the National Institute of Allergy and Infectious Diseases (grants R01AI143333, R01AI110324, U01AI100031, U01AI075115, R01AI110324, R01AI102939, and K01AI125086-01), the National Institute of Mental Health (grants R01MH115799, R01MH107275, R01 MH128232, F31MH134699), and the Division of Intramural Research of the National Institute for Allergy and Infectious Diseases.

AUTHOR CONTRIBUTIONS

SAG, JSS, ISC, TL, YW, ES, SH, AND PK conceived and designed the study. ISC, JT and YW oversaw data cleaning and statistical analysis and directly accessed and verified the underlying data reported in the manuscript. AK and DM accessed the data, created the figures for the resubmission and edited the text. AK and DTL, FN, DS, JK, MKG, MJW, LWC, FMS oversaw data collection. All authors had full access to the data in the study, participated in the interpretation of data and revising the manuscript, and had final responsibility for the decision to submit for publication.

RESEARCH IN CONTEXT

Age-specific rates of HIV incidence are often highest among AYA and particularly young women. Risk factors for HIV infection among AYA include earlier sexual initiation, multiple partners, and inconsistent condom use. Combination prevention including community-wide uptake of ART and male medical circumcision has been associated with declines in HIV incidence in Rakai, Uganda in the overall population. A 2019 review of HIV incidence among adolescent girls and young women from 10 high-prevalence African countries found that few studies have examined incidence over time, and among those that there was limited evidence of incidence declines. Using data from 2005-2020 and the Rakai Community Cohort Study (RCCS) in southcentral Uganda, we found evidence that community-level factors including community viremia and ART use, VMMC among young men, and declines in sexual experience were associated with lower risk of HIV acquisition and seroprevalent infection among AYA. Declining HIV incidence and prevalence over time among AYA coincided with policy changes expanding access to ART and VMMC. Age of sexual initiation and community-level factors play critical roles in HIV transmission in Rakai and in declines over time in youth HIV incidence and prevalence. HIV prevention for AYA needs to address individual factors and public policies to improve access to ART and VMMC.