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Hepatitis B virus transmission by blood transfusion during 4 years of individual-donation nucleic acid testing in South Africa: estimated and observed window period risk

Authors

  • Marion Vermeulen,

    Corresponding author
    1. From the Donation Testing Department, South African National Blood Service (SANBS), Roodepoort, South Africa; the Hepatitis Virus Diversity Research Programme, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; and Lelie Research, Paris, France.
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    • These authors contributed equally to the study.

  • Caroline Dickens,

    1. From the Donation Testing Department, South African National Blood Service (SANBS), Roodepoort, South Africa; the Hepatitis Virus Diversity Research Programme, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; and Lelie Research, Paris, France.
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    • These authors contributed equally to the study.

  • Nico Lelie,

    1. From the Donation Testing Department, South African National Blood Service (SANBS), Roodepoort, South Africa; the Hepatitis Virus Diversity Research Programme, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; and Lelie Research, Paris, France.
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  • Evangelia Walker,

    1. From the Donation Testing Department, South African National Blood Service (SANBS), Roodepoort, South Africa; the Hepatitis Virus Diversity Research Programme, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; and Lelie Research, Paris, France.
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  • Charl Coleman,

    1. From the Donation Testing Department, South African National Blood Service (SANBS), Roodepoort, South Africa; the Hepatitis Virus Diversity Research Programme, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; and Lelie Research, Paris, France.
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  • Mark Keyter,

    1. From the Donation Testing Department, South African National Blood Service (SANBS), Roodepoort, South Africa; the Hepatitis Virus Diversity Research Programme, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; and Lelie Research, Paris, France.
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  • Ravi Reddy,

    1. From the Donation Testing Department, South African National Blood Service (SANBS), Roodepoort, South Africa; the Hepatitis Virus Diversity Research Programme, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; and Lelie Research, Paris, France.
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  • Robert Crookes,

    1. From the Donation Testing Department, South African National Blood Service (SANBS), Roodepoort, South Africa; the Hepatitis Virus Diversity Research Programme, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; and Lelie Research, Paris, France.
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  • Anna Kramvis

    1. From the Donation Testing Department, South African National Blood Service (SANBS), Roodepoort, South Africa; the Hepatitis Virus Diversity Research Programme, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; and Lelie Research, Paris, France.
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  • The sequence analysis in this study has been supported by a grant received from the National Research Foundation (NRF), South Africa (GUN 65530).

Marion Vermeulen, SANBS, 1 Constantia Boulevard, Constantia Kloof, Roodepoort, South Africa; e-mail: marion.vermeulen@sanbs.org.za.

Abstract

BACKGROUND: Since October 2005, a total of 2,921,561 blood donations have been screened by the South African National Blood Service for hepatitis B virus (HBV) by individual-donation nucleic acid testing (ID-NAT). Over 4 years, 149 hepatitis B surface antigen–negative acute-phase HBV NAT–positive donations were identified (1:19,608). The lookback program identified one probable HBV transmission.

STUDY DESIGN AND METHODS: The complete genomes of HBV isolated from the donor and recipient were sequenced, cloned, and analyzed phylogenetically. The HBV window period (WP) transmission risk was estimated assuming a minimum infectious dose of 3.7 HBV virions and an incidence rate correction factor of 1.34 for transient detectability of HBV DNA.

RESULTS: Of 149 acute-phase HBV NAT yields, 114 (1:25,627) were classified as pre–antibody to hepatitis B core antigen (anti-HBc) WP and 35 (1:83,473) as post–anti-HBc WP. The acute-phase transmission risk in the HBV DNA–negative pre- and post–anti-HBc WPs (of 15.3 and 1.3 days, respectively) was estimated at 1:40,000 and 1:480,000, respectively. One HBV transmission (1:2,900,000) was identified in a patient who received a transfusion from an ID-NAT–nonreactive donor in the pre–anti-HBc WP. Sequence analysis confirmed transmission of HBV Subgenotype A1 with 99.7% nucleotide homology between donor and recipient strains. The viral burden in the infectious red blood cell unit was estimated at 32 (22-43) HBV DNA copies/20 mL of plasma.

CONCLUSION: We report the first known case of transfusion-transmitted HBV infection by blood screened using ID-NAT giving an observed HBV transmission rate of 0.34 per million. The estimated pre–acute-phase transmission risk in the ID-NAT screened donor population was 73-fold higher than the observed WP transmission rate.

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