Richard J Hayes

Memorial Sloan-Kettering Cancer Center, New York, New York, United States

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Publications (313)2494.54 Total impact

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    ABSTRACT: Helminth (worm) infections cause morbidity among poor communities worldwide. An influential study conducted in Kenya in 1998-99 reported that a school-based drug-and-educational intervention had benefits regarding worm infections and school attendance. Effects were seen among children treated with deworming drugs, untreated children in intervention schools and children in nearby non-intervention schools. Combining these effects, the intervention was reported to increase school attendance by 7.5% in treated children. Effects on other outcomes (worm infections, anaemia, nutritional status and examination performance) were also investigated. In this pure replication, we used data provided by the original authors to re-analyse the study according to their methods. We compared these results against those presented in the original paper. Although most results were reproduced as originally reported, we identified discrepancies of several types between the original findings and re-analysis. For worm infections, re-analysis showed reductions similar to those originally reported. For anaemia prevalence, in contrast to the original findings, re-analysis found no evidence of benefit. For nutritional status, both original findings and re-analysis described modest evidence for a small improvement. For school attendance, re-analysis showed benefits similar to those originally found in intervention schools for both children who did and those who did not receive deworming drugs. However, after correction of coding errors, there was little evidence of an indirect effect on school attendance among children in schools close to intervention schools. Combining these effects gave a total increase in attendance of 3.9% among treated children, which was no longer statistically significant. As in the original results, re-analysis found no effect of the intervention on examination performance. Re-applying analytical approaches originally used, but correcting various errors, we found little evidence for some previously-reported indirect effects of a deworming intervention. Effects on worm infections, nutritional status, examination performance and school attendance on children in intervention schools were largely unchanged. © The Author 2015; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.
    International Journal of Epidemiology 07/2015; DOI:10.1093/ije/dyv127 · 9.20 Impact Factor
  • International Journal of Epidemiology 07/2015; DOI:10.1093/ije/dyv130 · 9.20 Impact Factor
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    ABSTRACT: Helminth (worm) infections cause morbidity among poor communities worldwide. An influential study conducted in Kenya in 1998-99 reported that a school-based drug-and-educational intervention had benefits for worm infections and school attendance. In this statistical replication, we re-analysed data from this cluster quasi- randomized stepped-wedge trial, specifying two co-primary outcomes: school attendance and examination performance. We estimated intention-to-treat effects using year-stratified cluster-summary analysis and observation-level random-effects regression, and combined both years with a random-effects model accounting for year. The participants were not blinded to allocation status, and other interventions were concurrently conducted in a sub-set of schools. A protocol guiding outcome data collection was not available. Quasi-randomization resulted in three similar groups of 25 schools. There was a substantial amount of missing data. In year-stratified cluster-summary analysis, there was no clear evidence for improvement in either school attendance or examination performance. In year-stratified regression models, there was some evidence of improvement in school attendance [adjusted odds ratios (aOR): year 1: 1.48, 95% confidence interval (CI) 0.88-2.52, P = 0.150; year 2: 1.23, 95% CI 1.01-1.51, P = 0.044], but not examination performance (adjusted differences: year 1: -0.135, 95% CI -0.323-0.054, P = 0.161; year 2: -0.017, 95% CI -0.201-0.166, P = 0.854). When both years were combined, there was strong evidence of an effect on attendance (aOR 1.82, 95% CI 1.74-1.91, P < 0.001), but not examination performance (adjusted difference -0.121, 95% CI -0.293-0.052, P = 0.169). The evidence supporting an improvement in school attendance differed by analysis method. This, and various other important limitations of the data, caution against over-interpretation of the results. We find that the study provides some evidence, but with high risk of bias, that a school-based drug-treatment and health-education intervention improved school attendance and no evidence of effect on examination performance. © The Author 2015; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.
    International Journal of Epidemiology 07/2015; DOI:10.1093/ije/dyv128 · 9.20 Impact Factor
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    ABSTRACT: Traditionally, health systems in sub-Saharan Africa have focused on acute conditions. Few data exist on the readiness of African health facilities (HFs) to address the growing burden of chronic diseases (CDs), specifically chronic, non-communicable diseases (NCDs). A stratified random sample of 28 urban and rural Ugandan HFs was surveyed to document the burden of selected CDs by analysing service statistics, service availability and service readiness using a modified WHO SARA questionnaire. Knowledge, skills and practice in the management of CDs of 222 health workers were assessed through a self-completed questionnaire. Among adult outpatient visits at hospitals, 33% were for CDs including HIV versus 14% and 4% at medium-sized and small health centres, respectively. Many HFs lacked guidelines, diagnostic equipment and essential medicines for primary management of CDs; training and reporting systems were weak. Lower-level facilities routinely referred patients with hypertension and diabetes. HIV services accounted for most CD visits and were stronger than NCD services. Systems were weaker in lower level HFs. Non-doctor clinicians and nurses lacked knowledge and experience in NCD care. Compared to higher level HFs, lower-level ones are less prepared and little used for CD care. Health systems in Uganda, particularly lower level HFs, urgently need improvement in managing common NCDs to cope with the growing burden. This should include the provision of standard guidelines, essential diagnostic equipment and drugs, training of health workers, supportive supervision and improved referral systems. Substantially better HIV basic service readiness demonstrates that improved NCD care is feasible. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
    Tropical Medicine & International Health 06/2015; DOI:10.1111/tmi.12560 · 2.30 Impact Factor
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    ABSTRACT: The burden of non-communicable diseases (NCDs) is increasing in sub-Saharan Africa, but data available for intervention planning are inadequate. We determined the prevalence of selected NCDs and HIV infection, and NCD risk factors in northwestern Tanzania and southern Uganda. A population-based cross-sectional survey was conducted, enrolling households using multistage sampling with five strata per country (one municipality, two towns, two rural areas). Consenting adults (≥18 years) were interviewed using the WHO STEPS survey instrument, examined, and tested for HIV and diabetes mellitus (DM). Adjusting for survey design, we estimated population prevalences of hypertension, DM, obstructive pulmonary disease, cardiac failure, epilepsy and HIV, and investigated factors associated with hypertension using logistic regression. Across strata, hypertension prevalence ranged from 16 % (95 % confidence interval (CI): 12 % to 22 %) to 17 % (CI: 14 % to 22 %) in Tanzania, and from 19 % (CI: 14 % to 26 %) to 26 % (CI: 23 % to 30 %) in Uganda. It was high in both urban and rural areas, affecting many young participants. The prevalence of DM (1 % to 4 %) and other NCDs was generally low. HIV prevalence ranged from 6 % to 10 % in Tanzania, and 6 % to 12 % in Uganda. Current smoking was reported by 12 % to 23 % of men in different strata, and 1 % to 3 % of women. Problem drinking (defined by Alcohol Use Disorder Identification Test criteria) affected 6 % to 15 % men and 1 % to 6 % women. Up to 46 % of participants were overweight, affecting women more than men and urban more than rural areas. Most patients with hypertension and other NCDs were unaware of their condition, and hypertension in treated patients was mostly uncontrolled. Hypertension was associated with older age, male sex, being divorced/widowed, lower education, higher BMI and, inversely, with smoking. The high prevalence of NCD risk factors and unrecognized and untreated hypertension represent major problems. The low prevalence of DM and other preventable NCDs provides an opportunity for prevention. HIV prevalence was in line with national data. In Tanzania, Uganda and probably elsewhere in Africa, major efforts are needed to strengthen health services for the early detection and treatment of chronic diseases.
    BMC Medicine 05/2015; 13(1):126. DOI:10.1186/s12916-015-0357-9 · 7.28 Impact Factor
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    ABSTRACT: A recent major cluster randomized trial of screening, active disease treatment, and mass isoniazid preventive therapy for 9 months during 2006-2011 among South African gold miners showed reduced individual-level tuberculosis incidence but no detectable population-level impact. We fitted a dynamic mathematical model to trial data and explored 1) factors contributing to the lack of population-level impact, 2) the best-achievable impact if all implementation characteristics were increased to the highest level achieved during the trial ("optimized intervention"), and 3) how tuberculosis might be better controlled with additional interventions (improving diagnostics, reducing treatment delay, providing isoniazid preventive therapy continuously to human immunodeficiency virus-positive people, or scaling up antiretroviral treatment coverage) individually and in combination. We found the following: 1) The model suggests that a small proportion of latent infections among human immunodeficiency virus-positive people were cured, which could have been a key factor explaining the lack of detectable population-level impact. 2) The optimized implementation increased impact by only 10%. 3) Implementing additional interventions individually and in combination led to up to 30% and 75% reductions, respectively, in tuberculosis incidence after 10 years. Tuberculosis control requires a combination prevention approach, including health systems strengthening to minimize treatment delay, improving diagnostics, increased antiretroviral treatment coverage, and effective preventive treatment regimens. © The Author 2015. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
    American journal of epidemiology 03/2015; 181(8). DOI:10.1093/aje/kwu320 · 4.98 Impact Factor
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    ABSTRACT: Reflecting on a Policy Forum article by Till Bärnighausen and colleagues, the HPTN 071 (PopART) Study Team consider ethical and study power concerns and the importance of the trial's future findings.
    PLoS Medicine 03/2015; 12(3):e1001800. DOI:10.1371/journal.pmed.1001800 · 14.00 Impact Factor
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    ABSTRACT: Despite a recent decline, Zimbabwe still has the fifth highest adult HIV prevalence in the world at 14.7%; 56% of the population are currently living in extreme poverty. Cross-sectional population-based survey of 18-22 year olds, conducted in 30 communities in south-eastern Zimbabwe in 2007. To examine whether the risk of HIV infection among young rural Zimbabwean women is associated with socio-economic position and whether different socio-economic domains, including food sufficiency, might be associated with HIV risk in different ways. Eligible participants completed a structured questionnaire and provided a finger-prick blood sample tested for antibodies to HIV and HSV-2. The relationship between poverty and HIV was explored for three socio-economic domains: ability to afford essential items; asset wealth; food sufficiency. Analyses were performed to examine whether these domains were associated with HIV infection or risk factors for infection among young women, and to explore which factors might mediate the relationship between poverty and HIV. 2593 eligible females participated in the survey and were included in the analyses. Overall HIV prevalence among these young females was 7.7% (95% CI: 6.7-8.7); HSV-2 prevalence was 11.2% (95% CI: 9.9-12.4). Lower socio-economic position was associated with lower educational attainment, earlier marriage, increased risk of depression and anxiety disorders and increased reporting of higher risk sexual behaviours such as earlier sexual debut, more and older sexual partners and transactional sex. Young women reporting insufficient food were at increased risk of HIV infection and HSV-2. This study provides evidence from Zimbabwe that among young poor women, economic need and food insufficiency are associated with the adoption of unsafe behaviours. Targeted structural interventions that aim to tackle social and economic constraints including insufficient food should be developed and evaluated alongside behaviour and biomedical interventions, as a component of HIV prevention programming and policy.
    PLoS ONE 01/2015; 10(1):e0115290. DOI:10.1371/journal.pone.0115290 · 3.23 Impact Factor
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    ABSTRACT: Observational studies of a putative association between hormonal contraception (HC) and HIV acquisition have produced conflicting results. We conducted an individual participant data (IPD) meta-analysis of studies from sub-Saharan Africa to compare the incidence of HIV infection in women using combined oral contraceptives (COCs) or the injectable progestins depot-medroxyprogesterone acetate (DMPA) or norethisterone enanthate (NET-EN) with women not using HC. Eligible studies measured HC exposure and incident HIV infection prospectively using standardized measures, enrolled women aged 15-49 y, recorded ≥15 incident HIV infections, and measured prespecified covariates. Our primary analysis estimated the adjusted hazard ratio (aHR) using two-stage random effects meta-analysis, controlling for region, marital status, age, number of sex partners, and condom use. We included 18 studies, including 37,124 women (43,613 woman-years) and 1,830 incident HIV infections. Relative to no HC use, the aHR for HIV acquisition was 1.50 (95% CI 1.24-1.83) for DMPA use, 1.24 (95% CI 0.84-1.82) for NET-EN use, and 1.03 (95% CI 0.88-1.20) for COC use. Between-study heterogeneity was mild (I2 < 50%). DMPA use was associated with increased HIV acquisition compared with COC use (aHR 1.43, 95% CI 1.23-1.67) and NET-EN use (aHR 1.32, 95% CI 1.08-1.61). Effect estimates were attenuated for studies at lower risk of methodological bias (compared with no HC use, aHR for DMPA use 1.22, 95% CI 0.99-1.50; for NET-EN use 0.67, 95% CI 0.47-0.96; and for COC use 0.91, 95% CI 0.73-1.41) compared to those at higher risk of bias (pinteraction = 0.003). Neither age nor herpes simplex virus type 2 infection status modified the HC-HIV relationship. This IPD meta-analysis found no evidence that COC or NET-EN use increases women's risk of HIV but adds to the evidence that DMPA may increase HIV risk, underscoring the need for additional safe and effective contraceptive options for women at high HIV risk. A randomized controlled trial would provide more definitive evidence about the effects of hormonal contraception, particularly DMPA, on HIV risk.
    PLoS Medicine 01/2015; 12(1). DOI:10.1371/journal.pmed.1001778 · 15.25 Impact Factor
  • AIDS research and human retroviruses; 10/2014
  • AIDS Research and Human Retroviruses 10/2014; 30 Suppl 1(S1):A72-3. DOI:10.1089/aid.2014.5134.abstract · 2.46 Impact Factor
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    ABSTRACT: Self-testing for HIV infection may contribute to early diagnosis of HIV, but without necessarily increasing antiretroviral therapy (ART) initiation.
    JAMA The Journal of the American Medical Association 07/2014; 312(4):372-9. DOI:10.1001/jama.2014.6493 · 30.39 Impact Factor
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    ABSTRACT: Background Curable, non-viral pathogens account for a significant burden of sexually transmitted infections (STIs), and there is established evidence that STIs increase both HIV acquisition and transmission. We investigated the prevalence, trends, and factors associated with Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis and Treponema pallidum, and the performance of syndromic management, among a cohort of women working in bars, hotels, and other food and recreational facilities near large-scale mines in northwestern Tanzania. Methods HIV-negative women aged 18–44 years (N = 966) were enrolled and followed for 12 months in a microbicides feasibility study. We collected sociodemographic and behavioural data, performed clinical examinations, and tested for STIs, at enrolment and 3-monthly. Risk factors for STIs were investigated using logistic regression models with random effects. Sensitivity, specificity and predictive values of syndromic management were calculated. Results At enrolment, the prevalences of C. trachomatis, N. gonorrhoeae, T. vaginalis, and high-titre active syphilis were 111/956 (12%), 42/955 (4%), 184/945 (19%) and 46/965 (5%), respectively. There were significant decreases over time for C. trachomatis and T. vaginalis (OR trend per month: 0.94 [95% CI 0.91, 0.97]; and 0.95 [0.93, 0.98], respectively; both p<0.001). The majority of these infections were not diagnosed by the corresponding syndrome; therefore, most participants were not treated at the diagnosis visit. Syndromic management was poorly predictive of laboratory-diagnosed infections. We identified a number of risk factors for STIs, including low educational level, some sexual behaviours, and ever having been pregnant. Conclusions This analysis demonstrates that the prevalences of curable STIs are high among women who work in food and recreational facilities in northwestern Tanzania. Most of these infections are missed by syndromic management. Accurate and affordable rapid-point-of-care tests and innovative interventions are needed to reduce the burden of STIs in this population which is at increased risk for HIV.
    PLoS ONE 07/2014; 9(7):e101221. DOI:10.1371/journal.pone.0101221 · 3.23 Impact Factor
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    ABSTRACT: Do injectable and oral contraceptives increase the risk of human immunodeficiency virus (HIV) acquisition in women?
    Human Reproduction 05/2014; 29(8). DOI:10.1093/humrep/deu113 · 4.59 Impact Factor
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    ABSTRACT: Historically, health facilities in sub-Saharan Africa have mainly managed acute, infectious diseases. Few data exist for the preparedness of African health facilities to handle the growing epidemic of chronic, non-communicable diseases (NCDs). We assessed the burden of NCDs in health facilities in northwestern Tanzania and investigated the strengths of the health system and areas for improvement with regard to primary care management of selected NCDs. Between November, 2012, and May, 2013, we undertook a cross-sectional survey of a representative sample of 24 public and not-for-profit health facilities in urban and rural Tanzania (four hospitals, eight health centres, and 12 dispensaries). We did structured interviews of facility managers, inspected resources, and administered self-completed questionnaires to 335 health-care workers. We focused on hypertension, diabetes, and HIV (for comparison). Our key study outcomes related to service provision, availability of guidelines and supplies, management and training systems, and preparedness of human resources. Of adult outpatient visits to hospitals, 58% were for chronic diseases compared with 20% at health centres, and 13% at dispensaries. In many facilities, guidelines, diagnostic equipment, and first-line drug therapy for the primary care of NCDs were inadequate, and management, training, and reporting systems were weak. Services for HIV accounted for most chronic disease visits and seemed stronger than did services for NCDs. Ten (42%) facilities had guidelines for HIV whereas three (13%) facilities did for NCDs. 261 (78%) health workers showed fair knowledge of HIV, whereas 198 (59%) did for hypertension and 187 (56%) did for diabetes. Generally, health systems were weaker in lower-level facilities. Front-line health-care workers (such as non-medical-doctor clinicians and nurses) did not have knowledge and experience of NCDs. For example, only 74 (49%) of 150 nurses had at least fair knowledge of diabetes care compared with 85 (57%) of 150 for hyptertension and 119 (79%) of 150 for HIV, and only 31 (21%) of 150 had seen more than five patients with diabetes in the past 3 months compared with 50 (33%) of 150 for hypertension and 111 (74%) of 150 for HIV. Most outpatient services for NCDs in Tanzania are provided at hospitals, despite present policies stating that health centres and dispensaries should provide such services. We identified crucial weaknesses (and strengths) in health systems that should be considered to improve primary care for NCDs in Africa and identified ways that HIV programmes could serve as a model and structural platform for these improvements. UK Medical Research Council.
    The Lancet Global Health 05/2014; 2(5):e285-e292. DOI:10.1016/S2214-109X(14)70033-6 · 10.04 Impact Factor
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    ABSTRACT: Background. Human papillomavirus (HPV) vaccines are recommended for girls prior to sexual debut because they are most effective if administered before girls acquire HPV. Little research has been done on HPV prevalence in girls who report not having passed sexual debut in high HPV-prevalence countries. Methods. Using attendance registers of randomly selected primary schools in the Mwanza region of Tanzania, we enrolled girls aged 15–16 years who reported not having passed sexual debut. A face-to-face interview on sexual behavior and intravaginal practices, and a nurse-assisted self-administered vaginal swab were performed. Swabs were tested for 13 high-risk and 24 low-risk HPV genotypes. Results. HPV was detected in 40/474 (8.4%; 95% confidence interval [CI], 5.9–11.0) girls. Ten different high-risk and 21 different low-risk genotypes were detected. High-risk genotypes were detected in 5.3% (95% CI, 3.5–7.8). In multivariable analysis, only intravaginal cleansing (practiced by 20.9%) was associated with HPV detection (adjusted odds ratio = 2.19, 95% CI, 1.09–4.39). Conclusion. This cohort of adolescent Tanzanian girls had a high HPV prevalence prior to self-reported sexual debut, and this was associated with intravaginal cleansing. This most likely reflects underreporting of sexual activity, and it is possible that intravaginal cleansing is a marker for unreported sexual debut or nonpenetrative sexual behaviors.
    The Journal of Infectious Diseases 04/2014; 210(6). DOI:10.1093/infdis/jiu202 · 5.78 Impact Factor
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    ABSTRACT: Cross-sectional studies have shown a strong association between Mycoplasma genitalium and HIV infections. We previously reported that in a cohort of female sex workers in Uganda, M genitalium infection at baseline was associated with HIV seroconversion. Here we examine the temporal association between the M genitalium infection status shortly before HIV seroconversion and HIV acquisition. A nested case-control study was conducted within a cohort of women at high risk for HIV in Kampala. Cases were those of women acquiring HIV within 2 years of enrolment. For each of the 42 cases, 3 controls were selected from women HIV negative at the visit when the corresponding case first tested HIV seropositive. The association between HIV acquisition and M genitalium infection immediately prior to HIV testing was analysed using conditional logistic regression. There was weak evidence of an association between M genitalium infection and HIV acquisition overall (crude OR=1.57; 95% CI 0.67 to 3.72, aOR=2.28: 95% CI 0.81 to 6.47). However, time of M genitalium testing affected the association (p value for effect-modification=0.004). For 29 case-control sets with endocervical samples tested 3 months prior to the first HIV-positive result, M genitalium infection increased the risk of HIV acquisition (crude OR=3.09; 95% CI 1.06 to 9.05, aOR=7.19; 95% CI 1.68 to 30.77), whereas there was little evidence of an association among the 13 case-control sets with samples tested at an earlier visit (crude OR=0.30: 95% CI 0.04 to 2.51; aOR=0.34; 95% CI 0.02 to 5.94). Our study showed evidence of a temporal relationship between M genitalium infection and HIV acquisition that suggests that M genitalium infection may be a co-factor in the acquisition of HIV infection.
    Sexually transmitted infections 03/2014; 90(7). DOI:10.1136/sextrans-2013-051467 · 3.08 Impact Factor
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    ABSTRACT: Effective interventions to reduce HIV incidence in sub-Saharan Africa are urgently needed. Mathematical modelling and the HIV Prevention Trials Network (HPTN) 052 trial results suggest that universal HIV testing combined with immediate antiretroviral treatment (ART) should substantially reduce incidence and may eliminate HIV as a public health problem. We describe the rationale and design of a trial to evaluate this hypothesis. A rigorously-designed trial of universal testing and treatment (UTT) interventions is needed because: i) it is unknown whether these interventions can be delivered to scale with adequate uptake; ii) there are many uncertainties in the models such that the population-level impact of these interventions is unknown; and ii) there are potential adverse effects including sexual risk disinhibition, HIV-related stigma, over-burdening of health systems, poor adherence, toxicity, and drug resistance.In the HPTN 071 (PopART) trial, 21 communities in Zambia and South Africa (total population 1.2 m) will be randomly allocated to three arms. Arm A will receive the full PopART combination HIV prevention package including annual home-based HIV testing, promotion of medical male circumcision for HIV-negative men, and offer of immediate ART for those testing HIV-positive; Arm B will receive the full package except that ART initiation will follow current national guidelines; Arm C will receive standard of care. A Population Cohort of 2,500 adults will be randomly selected in each community and followed for 3 years to measure the primary outcome of HIV incidence. Based on model projections, the trial will be well-powered to detect predicted effects on HIV incidence and secondary outcomes. Trial results, combined with modelling and cost data, will provide short-term and long-term estimates of cost-effectiveness of UTT interventions. Importantly, the three-arm design will enable assessment of how much could be achieved by optimal delivery of current policies and the costs and benefits of extending this to UTT.Trial registration: ClinicalTrials.gov NCT01900977.
    Trials 02/2014; 15(1):57. DOI:10.1186/1745-6215-15-57 · 2.12 Impact Factor
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    Journal of epidemiology and community health 02/2014; 68(7). DOI:10.1136/jech-2013-202507 · 3.29 Impact Factor

Publication Stats

12k Citations
2,494.54 Total Impact Points

Institutions

  • 2015
    • Memorial Sloan-Kettering Cancer Center
      New York, New York, United States
  • 1994–2015
    • London School of Hygiene and Tropical Medicine
      • • Faculty of Epidemiology and Population Health
      • • Department of Infectious Disease Epidemiology
      • • Department of Clinical Research
      • • Tropical Epidemiology Group (TEG)
      Londinium, England, United Kingdom
  • 2014
    • University of East London
      • Institute for Health and Human Development
      Londinium, England, United Kingdom
  • 2012
    • Medical Research Council / Uganda Virus Research Institute
      Entebbe, Central Region, Uganda
  • 2010
    • University College London
      • Department of Infection and Population Health
      Londinium, England, United Kingdom
    • Mwanza Intervention Trials Unit
      Mwansa, Mwanza, Tanzania
  • 2001–2010
    • National Institute for Medical Research (NIMR)
      Dār es Salām, Dar es Salaam, Tanzania
  • 2009
    • The Aurum Institute
      Johannesburg, Gauteng, South Africa
  • 2007
    • University of Glasgow
      • MRC/CSO Social and Public Health Sciences Unit
      Glasgow, Scotland, United Kingdom
    • Harvard Medical School
      Boston, Massachusetts, United States
  • 2004–2007
    • Erasmus Universiteit Rotterdam
      • Department of Public Health (MGZ)
      Rotterdam, South Holland, Netherlands
  • 2006
    • Uganda Virus Research Institute
      Entebbe, Central Region, Uganda
  • 2002–2006
    • University of Zimbabwe
      Salisbury, Harare, Zimbabwe
    • University of the Witwatersrand
      Johannesburg, Gauteng, South Africa
    • Bugando Medical Centre
      Mwansa, Mwanza, Tanzania
  • 2003
    • Johns Hopkins University
      Baltimore, Maryland, United States
  • 1995
    • Institute Of Tropical Medicine
      Antwerpen, Flemish, Belgium
  • 1993
    • University of Zambia
      • School of Medicine
      Lusaka, Lusaka Province, Zambia
  • 1992
    • Kenyatta National Hospital
      Nairoba, Nairobi Area, Kenya