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Geoff Garnett

Publications and source records attributed to Geoff Garnett.

7 recordsLinked to original sources
PubMed2006

Simulations of the HIV epidemic in sub-Saharan Africa: sexual transmission versus transmission through unsafe medical injections.

OBJECTIVES: Heterosexual transmission has long been considered the predominant route of transmission of HIV-1 in sub-Saharan Africa. However, some have argued that unsafe medical injections account for the majority of transmission in this region. GOAL: The goal of this study was to compare the HIV-1 epidemics associated with different transmission routes. STUDY: An age-structured deterministic compartmental model of HIV-1 transmission through both sexual contact and unsafe injections was developed and simulations of sexual transmission and iatrogenic transmission were compared with observed prevalence. RESULTS: Iatrogenic transmission probabilities and numbers of unsafe injections required to generate observed prevalence are unfeasibly high. Simulations of sexually transmitted HIV-1 generate observed prevalence using transmission probabilities and average partner change rates that are within plausible bounds. CONCLUSIONS: Heterosexual transmission seems a more likely route of transmission in the region. However, heterogeneity in contact patterns is of key importance. Further information on groups who are likely to receive more injections is required.

Adolescent↗
PubMed2006

Thomas Bell.

Explore the source record for details and available documents.

Education, Dental↗
PubMed2005

Metaanalysis and metaregression in interpreting study variability in the impact of sexually transmitted diseases on susceptibility to HIV infection.

BACKGROUND: Observational studies examining the effects of other sexually transmitted diseases (STDs) on HIV susceptibility differ in the populations observed and in which "other STDs" are examined. The extent to which an STD alters the risk of transmission of HIV may vary according to disease and population characteristics. GOALS: The goals of this study were to review studies examining the effect of other STDs on HIV-1 susceptibility and to correlate their effect estimates with type of "other STD", study design, and population characteristics. STUDY: Relevant studies with longitudinal design were identified through a systematic search of the PubMed database, and their evidence was critically evaluated. Metaregression techniques were then used to correlate study characteristics with corresponding effect estimates. RESULTS: Of 31 studies included, 4 contained direct data on exposure to HIV-1. Three of these were inconclusive, the fourth indicating a strong relationship between STDs and transmission of HIV. Pooled effect estimates using all studies are statistically significant and indicate a 2- to 3-fold increase in risk of HIV-1 acquisition. Effect estimates corresponding some of the "other STD" categories exhibit heterogeneity, but no significant associations with study characteristics were found. CONCLUSIONS: Most of the studies lack direct exposure data, lending them susceptible to exposure bias. Another problem may be measurement error about risk factors and STD status at time of HIV-1 infection. Because direct exposure data are difficult to come by (4 of 31 studies contained such data, all but 1 inconclusive), future observational studies on the influence of STDs on HIV-1 transmission should include quantitative analyses of the sensitivity of results to potential confounding and measurement error if they are to further understanding.

Bias↗
PubMed2003

The impact of migration on HIV-1 transmission in South Africa: a study of migrant and nonmigrant men and their partners.

BACKGROUND: To investigate the association between migration and HIV infection among migrant and nonmigrant men and their rural partners. GOAL: The goal was to determine risk factors for HIV-1 infection in South Africa. STUDY DESIGN: This was a cross-sectional study of 196 migrant men and 130 of their rural partners, as well as 64 nonmigrant men and 98 rural women whose partners are nonmigrant. Male migrants were recruited at work in two urban centers, 100 km and 700 km from their rural homes. Rural partners were traced and invited to participate. Nonmigrant couples were recruited for comparison. The study involved administration of a detailed questionnaire and blood collection for HIV testing. RESULTS: Testing showed that 25.9% of migrant men and 12.7% of nonmigrant men were infected with HIV ( P= 0.029; odds ratio = 2.4; 95% CI = 1.1-5.3). In multivariate analysis, main risk factors for male HIV infection were being a migrant, ever having used a condom, and having lived in four or more places during a lifetime. Being the partner of a migrant was not a significant risk factor for HIV infection among women; significant risk factors were reporting more than one current regular partner, being younger than 35 years, and having STD symptoms during the previous 4 months. CONCLUSION: Migration is an independent risk factor for HIV infection among men. Workplace interventions are urgently needed to prevent further infections. High rates of HIV were found among rural women, and the migration status of the regular partner was not a major risk factor for HIV. Rural women lack access to appropriate prevention interventions, regardless of their partners' migration status.

Adult↗