The Bissau HIV Cohort – A West African cohort with a high prevalence of HIV-2

Sanne Jespersen1,2, Bo Langhoff Hønge1,2, Inés Oliveira1, Candida Medina3, David da Silva Te3, Faustino Gomes Correira3, Christian Erikstrup4, Alex Lund Laursen2, Lars Østergaard2, Christian Wejse1,2,5, for The Bissau HIV Cohort study group
Affiliates: 1Bandim Health Project, Indepth Network, Bissau, Guinea-Bissau. 2Department of Infectious Diseases, Aarhus University Hospital, Denmark. 3National HIV Programme, Ministry of Health, Bissau, Guinea-Bissau. 4Department of Clinical Immunology, Aarhus University Hospital, Denmark. 5GloHAU, Center for Global Health, School of Public Health, Aarhus University, Denmark.

Background
The West African country Guinea-Bissau is home to the world’s highest prevalence of HIV-2 and its HIV-1 prevalence is rising. The Bissau HIV Cohort was started in 2007 to gain new insights into the overall effect of introducing antiretroviral treatment in a population with concomitant infection with three retroviruses (HIV-1, HIV-2, and human T-lymphotropic virus type 1 (HTLV-1)). We here provide a description of The Bissau HIV Cohort and present research results obtained within the cohort.

Methods
The Bissau HIV Cohort was started by physicians from the Bandim Health Project, Aarhus University Hospital, Denmark, and Hospital Nacional Simão Mendes (HNSM), the main hospital in Bissau, the capital of Guinea-Bissau. All HIV infected individuals attending the HIV clinic at HNSM are invited to be included in the cohort. Demographic and clinical data are collected at baseline and every six months, together with CD4 cell count and routine biochemistry tests. Plasma and cells are stored in a bio repository in Denmark.

Results
From July 2007 to June 2013, 3762 HIV infected patients were included in the cohort. Baseline characteristics are presented in Table 1. Research has been conducted within the following areas:
1) Laboratory capacity: a) The HIV rapid test SD Bioline HIV 1/2 3.0 overestimates the number of HIV-1/2 dual infections, while HBsAg and anti-HCV rapid tests underestimate hepatitis prevalence. b) Biochemistry and CD4 measurements: Major interruptions in availability contribute to delayed initiation of ART, late diagnosis of treatment failure and lack of diagnosis of adverse events. c) Since viral load measurements are still not available in Guinea-Bissau we identified simple and inexpensive markers of disease progression in HIV.
2) Loss to follow-up is a major problem and occurs in all stages during the diagnostics and follow-up period. Identifying risk factors enables us to target interventions to improve retention in care.
3) Clinical trials: a) The Bissau HIV Cohort has been used as a platform for performing a randomized controlled trial of a therapeutic HIV vaccine demonstrating that therapeutic immunization is feasible. b) Results from the PIONA trial comparing a protease inhibitor (PI)-based treatment regimen to an NNRTI-based regimen in HIV-1 are pending.

Ongoing research involves studies to improve TB diagnosis in cohort patients; studies on co-infection with hepatitis B, C and D; qualitative and quantitative studies of how to decrease LTFU and improve adherence; immunological studies; assessment of sex-based effects; and evaluation of non-specific effects on HIV of vaccines against other diseases than HIV.

Conclusions
The Bissau HIV Cohort comprises the world’s largest cohort of HIV-2 and HIV-1/2 dually infected patients. The cohort represents a unique opportunity to study how co-infections alter immune response, disease progression, and response to treatment. Research within the cohort has focused on the problems faced while delivering care for HIV infected patients in a low resource setting. Potential collaborators are invited to contact the chair of the cohort study group, Christian Wejse (e-mail: wejse@dadlnet.dk).

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