The epidemiology of HIV-1 and other STDs in trucking workers in Kenya: preparations for HIV-1 vaccine trials

Jackson, Denis James (1998) The epidemiology of HIV-1 and other STDs in trucking workers in Kenya: preparations for HIV-1 vaccine trials. MD thesis, University of Glasgow.

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A cohort of HIV-1 seronegative male trucking company workers was established in the Kenyan coastal city of Mombasa, for the purposes of preparing them for HIV-1 preventive vaccine trials. The cohort was one of only three prospective male cohorts which have published data on heterosexual HIV-1 acquisition in sub-Saharan Africa, the continent most affected by this pandemic. HIV-1 seroincidence was measured and correlates of HIV-1 acquisition, including other STDs, were examined. Results of almost three year's of follow-up, and data on anticipated acceptance of the conditions of an HIV-1 vaccine trial are presented. o The baseline seroprevalence for antibodies to HIV-1 was 17% and the prevalence of active syphilis was 4.5%. o HIV-1 seroincidence was 4.0% per annum in 990 person years of follow-up. Multivariate Hazard analysis revealed a strong association between HIV-1 acquisition and occupation of driver or assistant (HR 4.0, 95% CI: 2.1-7.9), any sex with a partner other than a spouse (HR 4.2, 95% CI: 1.3-13.6), and a trend towards higher incidence with uncircumcised status (HR 2.0, 95% CI: 0.9-4.6). No association between STD and HIV-1 acquisition was found with an observed incidence of symptomatic gonococcal and non-gonococcal urethral discharge of 18.2% per annum, and 4.3% per annum for genital ulcer disease. o There were highly significant declines in extramarital sexual contacts from 50% to 40% in three month follow-up time blocks (p<0.001), and sex worker contacts from 12% to 6% (p=0.001), in a time trends analysis which included 494 person- years of follow-up. No significant change in condom use was recorded over time. Consistent (100%) condom use remained at approximately 30% of men engaging in extramarital sex with a partner other than a spouse. o Highly significant declines in the incidence of observed and reported sexually transmitted diseases were measured over the course of follow-up (p<0.001) in the first 494 person-years of follow-up. In the absence of data from the general population, it is not possible to attribute these declines to the behavioural and treatment interventions of the project, but it does document that the climate is right for behaviour change, and decrease in STD acquisition, in men in this setting. o Prevalence of symptomatic and asymptomatic urethral infections {N gonorrhoeae, C trachomatis, or T vaginalis) was 11.5% in a cross-sectional study which included HIV-1 seropositive men, following the documented decline in symptomatic STDs. Over two thirds of infections were asymptomatic. The leucocyte esterase dipstick (LED) urine screening test for urethral inflammation had a sensitivity of 55% and a specificity of 82%, in asymptomatic men. The LED test was the most accurate predictor of asymptomatic urethral infection. Risk assessment on the basis of demographic and behavioural characteristics did not prove useful. T vaginalis was the most common urethral infection and was associated with older age. o Eighty six per cent of 201 HIV-1 seronegative men interviewed in a vaccine acceptability survey stated that they felt at personal risk of HIV infection, and 84%) of men declared interest in participation in an HIV preventive vaccine trial. However, 17% of men stated that they would increase risk behaviour if they pai'ticipated in an HIV vaccine trial.

Item Type: Thesis (MD)
Qualification Level: Doctoral
Colleges/Schools: College of Medical Veterinary and Life Sciences
Supervisor's Name: Kreiss, J. K.
Date of Award: 1998
Depositing User: Mrs Monika Milewska-Fiertek
Unique ID: glathesis:1998-31021
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 08 Nov 2018 12:07
Last Modified: 08 Nov 2018 12:07
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