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Evidence of Declining HIV Infection Rates in Uganda: Implications for Community-based HIV Vaccine Efficacy Trials
David Guwatudde*1,2, M Eller2, L Eller2, M Millard2, H Kibuuka2, F Wabwire-Mangen1,2, N Sewankambo3, D Serwadda1, N Michael4, M Robb5, and The Kayunga District Cohort Development Research Team
1Makerere Univ Johns Hopkins Univ Res Collaboration, Kampala, Uganda; 2Makerere Univ-Walter Reed Project, Kampala, Uganda; 3Makerere Univ Sch of Med, Kampala, Uganda; 4Walter Reed Army Inst of Res, Rockville, MD, US; and 5Henry M Jackson Fndn, Rockville, MD, US
Background: Few community-based studies have been
conducted to assess prevalence and incidence of HIV infection in Uganda. We report results from a community-based cohort study, which is part of preparatory
research for HIV vaccine efficacy trials being conducted by the Makerere
University-Walter Reed Project in Uganda. The primary objectives of the study
were to determine HIV prevalence, incidence, participant retention, and
willingness to participate in HIV vaccine efficacy trials.
Methods: Consenting volunteers aged 15 to 49 years
from the rural community of Kayunga District in Uganda were enrolled between
March and July 2006. A baseline questionnaire that collected information on
demographics, sexuality, and other relevant data was administered. A blood
sample was obtained at each study visit for HIV, and other tests. Participants
were followed and evaluated every 6 months.
Results: A total of 2025 cohort participants were
enrolled. Overall HIV prevalence was 9.9% with significantly higher prevalence
among females (12.5%) versus males (7%, p <0.001). Prevalence was
highest in subjects aged 44 to 49 years (18%) and gradually declined in younger
age groups. Prevalence of other selected infections were: hepatitis B, 4.6%;
Hepatitis C, 0.6%; and syphilis,11.0%. After 1 year of follow-up, overall
annual HIV incidence was 0.77%. Of the 13 incident cases, 9 were females
(annual incidence 1.02%) versus 4 cases among males (annual incidence 0.49%).
Annual incidence was also highest in the age group 25 to 29 years (1.68%),
followed by the 35 to 39 years (1.05%) and the 30 to 34 years groups (0.99%).
Cohort retention after 1 year of follow-up was 87%. Loss to follow-up was
highest in the age groups younger than 25 years with an average of 21.4%,
compared to those aged 25 years or older with an average of 7.9% (p <0.001).
Conclusions: HIV incidence in this rural community
is insufficient to support vaccine efficacy trials. Overall annual incidence is
<1.0%, but slightly higher in age groups 25 years or older. These data
support evidence from surveillance activities showing decline in HIV incidence
in rural Uganda. Higher HIV risk groups within this community are being
prospectively followed to assess incidence and retention to best inform
subsequent HIV prevention and vaccine research efforts.
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