Browsing by Author "Zürcher S"

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Field performance of the Determine HBsAg point-of-care test for diagnosis of hepatitis B virus co-infection among HIV patients in Zambia.
(2018-Jan) Chisenga CC; Musukuma K; Chilengi R; Zürcher S; Munamunungu V; Siyunda A; Ojok D; Bauer S; Wandeler G; Vinikoor M; Institute for Infectious Diseases, University of Bern, Bern, Switzerland.; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia. Electronic address: caroline.chisenga@cidrz.org.; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia; School of Medicine, University of Zambia, Lusaka, Zambia.; Department of Infectious Diseases, Bern University Hospital and University of Bern, Bern, Switzerland; Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland.; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia; School of Medicine, University of Zambia, Lusaka, Zambia; Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)
BACKGROUND: We evaluated the field performance of a rapid point-of-care (POC) test for hepatitis B surface antigen (HBsAg) that could support decentralization and scale-up of hepatitis B virus (HBV) diagnosis in Africa. OBJECTIVE: To determine the field performance of the Determine HBsAg POC test for diagnosis of HBV co-infection among HIV patients in Zambia. STUDY DESIGN: Between 2013-2014, we screened HIV-infected adults for HBsAg at two urban clinics in Zambia. A subset were tested with the POC Determine HBsAg (Alere, USA) by finger prick in the clinic and HBsAg serology (Access2Analyzer, Beckman Coulter) at a reference laboratory. If either test was reactive, we determined HBV viral load (VL) and genotype. We described patient demographic and clinical characteristics (including liver fibrosis) and assessed the sensitivity, specificity, positive and negative predictive values (PPV and NPV) of the Determine test. In secondary analyses, we assessed sensitivity among patients with replicating HBV (i.e., VL>20 IU/ml) and with high HBV VL (i.e.,>20,000IU/ml). RESULTS: Among 412 participants with both HBsAg tests, median age was 34 years, 51% were women, and median CD4 was 208 cells/mm CONCLUSIONS: Determine HBsAg is a cheaper alternative HBV testing option compared to the gold standard ELISA and has high specificity and good sensitivity in the field among HIV-infected individuals.
Hepatitis B Infection, Viral Load and Resistance in HIV-Infected Patients in Mozambique and Zambia.
(2016) Wandeler G; Musukuma K; Zürcher S; Vinikoor MJ; Llenas-García J; Aly MM; Mulenga L; Chi BH; Ehmer J; Hobbins MA; Bolton-Moore C; Hoffmann CJ; Egger M; Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland.; Nucleo do investigacão Operational de Pemba, Pemba, Mozambique.; Centre for Infectious Disease Epidemiology and Research, University of Cape Town, Cape Town, South Africa.; Department of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, United States of America.; Institute for Infectious Diseases, University of Bern, Bern, Switzerland.; Department of Infectious Diseases, Bern University Hospital, University of Bern, Bern, Switzerland.; SolidarMed, Ancuabe, Mozambique.; Department of Infectious diseases, University of Dakar, Dakar, Senegal.; Department of Medicine at University of Alabama, Birmingham, United States of America.; SolidarMed, Lucerne, Switzerland.; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; Johns Hopkins University School of Medicine, Baltimore, United States of America.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)
BACKGROUND: Few data on the virological determinants of hepatitis B virus (HBV) infection are available from southern Africa. METHODS: We enrolled consecutive HIV-infected adult patients initiating antiretroviral therapy (ART) at two urban clinics in Zambia and four rural clinics in Northern Mozambique between May 2013 and August 2014. HBsAg screening was performed using the Determine® rapid test. Quantitative real-time PCR and HBV sequencing were performed in HBsAg-positive patients. Risk factors for HBV infection were evaluated using Chi-square and Mann-Whitney tests and associations between baseline characteristics and high level HBV replication explored in multivariable logistic regression. RESULTS: Seventy-eight of 1,032 participants in Mozambique (7.6%, 95% confidence interval [CI]: 6.1-9.3) and 90 of 797 in Zambia (11.3%, 95% CI: 9.3-13.4) were HBsAg-positive. HBsAg-positive individuals were less likely to be female compared to HBsAg-negative ones (52.3% vs. 66.1%, p<0.001). Among 156 (92.9%) HBsAg-positive patients with an available measurement, median HBV viral load was 13,645 IU/mL (interquartile range: 192-8,617,488 IU/mL) and 77 (49.4%) had high values (>20,000 UI/mL). HBsAg-positive individuals had higher levels of ALT and AST compared to HBsAg-negative ones (both p<0.001). In multivariable analyses, male sex (adjusted odds ratio: 2.59, 95% CI: 1.22-5.53) and CD4 cell count below 200/μl (2.58, 1.20-5.54) were associated with high HBV DNA. HBV genotypes A1 (58.8%) and E (38.2%) were most prevalent. Four patients had probable resistance to lamivudine and/or entecavir. CONCLUSION: One half of HBsAg-positive patients demonstrated high HBV viremia, supporting the early initiation of tenofovir-containing ART in HIV/HBV-coinfected adults.
Hepatitis B viral load in dried blood spots: A validation study in Zambia.
(2015-Nov) Vinikoor MJ; Zürcher S; Musukuma K; Kachuwaire O; Rauch A; Chi BH; Gorgievski M; Zwahlen M; Wandeler G; Department of Infectious Diseases, University Hospital Bern, Switzerland.; Institute of Infectious Diseases, University of Bern, Switzerland.; Institute of Social and Preventive Medicine, University of Bern, Switzerland.; Department of Medicine, University of Alabama at Birmingham, USA; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia; School of Medicine, University of Zambia, Lusaka, Zambia. Electronic address: mjv3@uab.edu.; Department of Infectious Diseases, University Hospital Bern, Switzerland; Institute of Social and Preventive Medicine, University of Bern, Switzerland; Department of Infectious Diseases, University of Dakar, Senegal.; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia; School of Medicine, University of Zambia, Lusaka, Zambia.; Department of Obstetrics and Gynecology, University of North Carolina at Chapel Hill, USA.; Centre for Infectious Disease Research in Zambia, Lusaka, Zambia.; CIDRZ; Centre for Infectious Disease Research in Zambia (CIDRZ)
BACKGROUND: Access to hepatitis B viral load (VL) testing is poor in sub-Saharan Africa (SSA) due to economic and logistical reasons. OBJECTIVES: To demonstrate the feasibility of testing dried blood spots (DBS) for hepatitis B virus (HBV) VL in a laboratory in Lusaka, Zambia, and to compare HBV VLs between DBS and plasma samples. STUDY DESIGN: Paired plasma and DBS samples from HIV-HBV co-infected Zambian adults were analyzed for HBV VL using the COBAS AmpliPrep/COBAS TaqMan HBV test (Version 2.0) and for HBV genotype by direct sequencing. We used Bland-Altman analysis to compare VLs between sample types and by genotype. Logistic regression analysis was conducted to assess the probability of an undetectable DBS result by plasma VL. RESULTS: Among 68 participants, median age was 34 years, 61.8% were men, and median plasma HBV VL was 3.98logIU/ml (interquartile range, 2.04-5.95). Among sequenced viruses, 28 were genotype A1 and 27 were genotype E. Bland-Altman plots suggested strong agreement between DBS and plasma VLs. DBS VLs were on average 1.59logIU/ml lower than plasma with 95% limits of agreement of -2.40 to -0.83log IU/ml. At a plasma VL ≥2,000IU/ml, the probability of an undetectable DBS result was 1.8% (95% CI: 0.5-6.6). At plasma VL ≥20,000IU/ml this probability reduced to 0.2% (95% CI: 0.03-1.7). CONCLUSIONS: In a Zambian laboratory, we observed strong agreement between DBS and plasma VLs and high sensitivity in DBS at plasma VL ≥2,000IU/ml. As HBV treatment expands, DBS could increase access to HBV VL testing and care in SSA settings.