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COMBINATION HIV PREVENTION AND HIV INCIDENCE IN RAKAI, UGANDA
Mary K. Grabowski1, Gertrude Nakigozi2, Fred Nalugoda2, Thomas Quinn1, Godfrey Kigozi2, Ronald H. Gray1, David Serwadda3, Maria Wawer1, Steven J. Reynolds4, Larry W. Chang1
1Johns Hopkins Univ, Baltimore, MD, USA,2Rakai Health Sciences Prog, Kalisizo, Uganda,3Makerere Univ, Kampala, Uganda,4NIAID, Washington, DC, USA
To assess the impact of combination HIV prevention (CHP) on HIV incidence, we measured long-term trends in HIV incidence based on observed seroconversion data in a prospective population-based cohort in Rakai, Uganda, and evaluated their associations with antiretroviral therapy use (ART), male circumcision (MC) scale-up, population-level viral load suppression, and sexual behaviors.
Between 1999 and 2016, data were collected in 12 surveys from 30 communities in the Rakai Community Cohort Study (RCCS), an open population-based longitudinal cohort of persons aged 15-49. Poisson regression was used to assess trends in HIV incidence, self-reported ART/MC coverage, population-level HIV viral load suppression (proportion of HIV-positive population with <1000 copies/ml), and sexual behaviors. Poisson multivariate regression with generalized estimating equations and robust variance estimators was used to estimate incidence rate ratios (IRR) and 95%CI of HIV incidence at each survey interval following the availability of ART/MC compared to the period prior to ART/MC scale-up.
Over the analysis period, 33,937 individuals participated in the RCCS, including 17,870 HIV-negative persons who contributed 94,427 person-years of follow-up and 931 incident HIV cases. ART was introduced in 2004 and by 2016 coverage was 69%. Increasing ART coverage was accompanied by significant changes in HIV viral load suppression rising from 42% in 2009 to 75% by 2016 among all HIV-positive persons (p<0.001). MC coverage increased from 15% in 1999 to 59% by 2016 (p<0.001). The only substantive changes in sexual behaviors occurred among persons 15-19 years reporting never having sex, which rose from 30% to 55% over the study period (p<0.001). Beginning in 2012, HIV incidence significantly declined as population-level coverage of CHP interventions were increased (Figure 1); by 2016 there was a 41% reduction in HIV incidence relative to the pre-ART/MC scale-up period from 1.17/100 py to 0.66/100 py (IRR: 0.56; 95%CI: 0.44-0.72; p<0.001; adjIRR:0.59: 95%CI: 0.45-0.77).
In this large prospective population-based study, HIV incidence significantly declined as ART and MC were scaled and sexual activity in young persons declined. These results provide empiric evidence that HIV control efforts utilizing combination interventions can have a substantial population-level impact