Relatively Low HIV Infection Rates in Rural Uganda, but with High Potential for a Rise: A Cohort Study in Kayunga District, Uganda

BACKGROUND: Few studies have been conducted in Uganda to identify and quantify the determinants of HIV-1 infection. We report results from a community-based cohort study whose primary objectives were to determine HIV-1 prevalence incidence and determinants of these infections among other objectives. METHODOLOGY: Consenting volunteers from the rural district of Kayunga in Uganda aged 15-49 years were enrolled between March and July 2006. Participants were evaluated every six months. A questionnaire that collected information on behavioral and other HIV-1 risk factors was administered and a blood sample obtained for laboratory analysis at each study visit. PRINCIPAL FINDINGS: HIV-1 prevalence among the 2025 participants was 9.9% (95% CI = 8.6%-11.2%). By the end of 12 months of follow-up 1689.7 person-years had been accumulated with a median follow-up time of 11.97 months. Thirteen HIV-1 incident cases were detected giving an annual HIV-1 incidence of 0.77% (95% CI = 0.35-1.19). Prevalence of HSV-2 infection was 57% and was strongly associated with prevalent HIV-1 infection (adjusted Odds Ratio = 3.9 95% CI = 2.50-6.17); as well as incident HIV-1 infection (adjusted Rate Ratio (RR) = 8.7 95% CI = 1.11-67.2). The single most important behavioral characteristic associated with incident HIV infection was the number of times in the past 6 months a participant had sex with person(s) they suspected/knew were having sex with others; attaining statistical significance at 10 times and higher (adjusted RR = 6.3 95% CI = 1.73-23.1). By the end of 12 months of follow-up 259 participants (13%) were lost to follow-up 13 (0.6%) had died and 2 (0.1%) had withdrawn consent. CONCLUSIONS: Despite relatively low HIV-1 incidence observed in this community prevalence remains relatively high. In the presence of high prevalence of HSV-2 infection and the behavioral characteristic of having sex with more than one partner there is potential for increase in HIV-1 incidence.