Browsing by Author "Robb, Merlin"

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    Contraceptive Use in Women Enrolled into Preventive HIV Vaccine Trials: Experience from a Phase I/II Trial in East Africa
    (PLoS ONE, 2009) Kibuuka, Hannah; Guwatudde, David; Kimutai, Robert; Maganga, Lucas; Maboko, Leonard; Watyema, Cecilia; Sawe, Fredrick; Shaffer, Douglas; Matsiko, Dickson; Millard, Monica; Michael, Nelson; Wabwire-Mangen, Fred; Robb, Merlin
    HIV vaccine trials generally require that pregnant women are excluded from participation, and contraceptive methods must be used to prevent pregnancy during the trial. However, access to quality services and misconceptions associated with contraceptive methods may impact on their effective use in developing countries. We describe the pattern of contraceptive use in a multi-site phase I/IIa HIV Vaccine trial in East Africa (Uganda, Kenya and Tanzania) and factors that may have influenced their use during the trial. Methods: Pregnancy prevention counseling was provided to female participants during informed consent process and at each study visit. Participants’ methods of contraception used were documented. Methods of contraceptives were provided on site. Pregnancy testing was done at designated visits during the trial. Obstacles to contraceptive use were identified and addressed at each visit. Results: Overall, 103 (31.8%) of a total of 324 enrolled volunteers were females. Female participants were generally young with a mean age of 29(67.2), married (49.5%) and had less than high school education (62.1%). Hormonal contraceptives were the most common method of contraception (58.3%) followed by condom use (22.3%). The distribution of methods of contraception among the three sites was similar except for more condom use and less abstinence in Uganda. The majority of women (85.4%) reported to contraceptive use prior to screening. The reasons for not using contraception included access to quality services, insufficient knowledge of certain methods, and misconceptions. Conclusion: Although hormonal contraceptives were frequently used by females participating in the vaccine trial, misconceptions and their incorrect use might have led to inconsistent use resulting in undesired pregnancies. The study underscores the need for an integrated approach to pregnancy prevention counseling during HIV vaccine trials.
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    Relatively Low HIV Infection Rates in Rural Uganda, but with High Potential for a Rise: A Cohort Study in Kayunga District, Uganda
    (PLoS ONE, 2009) Guwatudde, David; Wabwire-Mangen, Fred; Eller, Leigh Anne; Eller, Michael; McCutchan, Francine; Kibuuka, Hannah; Millard, Monica; Sewankambo, Nelson; Serwadda, David; Michael, Nelson; Robb, Merlin
    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.
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    Short Communication Colony-Forming Hematopoietic Progenitor Cells Are Not Preferentially Infected by HIV Type 1 Subtypes A and D in Vivo
    (AIDS research and human retroviruses, 2012) Mullis, Caroline E.; Oliver, Amy E.; Eller, Leigh Anne; Guwatudde, David; Mueller, Amy C.; Eller, Michael A.; Kibuuka, Hannah; Robb, Merlin; Quinn, Thomas C.; Redd, Andrew D.
    HIV subtype C has previously been shown to infect hematopoietic progenitor cells (HPCs) at a significantly higher rate than subtype B. To better understand the subtype-specific nature of HPC infection, we examined the prevalence of HPC infection in vivo by HIV-1 subtypes A and D. HIV-1 infection of HPC was examined in 40 individuals, 19 infected with subtype A and 21 with subtype D, using a single colony assay format. DNA from 1177 extracted colonies was tested for integrated viral DNA of the p24 gene. Four colonies were found to be stably infected, three of 462 colonies (0.65%) from HIV-1A-infected individuals (1/19 individuals) and one of 715 colonies (0.14%) from HIV-1D-infected individuals (1/22 individuals). These rates of colony infection were comparable to the rates observed in PBMCs from the same subjects. Additionally, no correlation was observed between cell colony density and circulating viral load or proviral load. Our findings suggest that HIV-1 subtypes A and D do not preferentially infect colony-forming HPCs over mature HIV target cells in vivo.