HBV viral load and drug resistance among HIV-HBV co-infected patients: a cross-sectional study in central South Africa

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Date
2021-12
Authors
Kotze, Jacobus Charles
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Publisher
University of the Free State
Abstract
In South Africa, human immunodeficiency virus (HIV) infected individuals co-infected with hepatitis B virus (HBV) do not routinely undergo HBV viral load (VL) testing when on antiretroviral therapy in the public sector treatment programme. We set out to explore whether HIV VL can be used as a proxy for HBV treatment response, since HIV VL testing is routinely performed in HIV/HBV co-infected patients. The clinical utility of HIV VL testing in this context may be impacted by the slower rate of viral decay which has been described for HBV as compared to HIV. In total, 224 patient samples were tested for HBV VL to determine the relatedness between HIV VL and HBV VL results. Samples with detectable HBV VL were sequenced to identify HBV associated drug mutations, hepatitis B surface antigen (HBsAg) mutations and genotype. Chi-square test for independence (χ2) was used to determine the relatedness between the viral loads, which indicated that the two viral loads are related (p-value<0.0001). However, in samples with an undetectable HIV VL, 29.27% (36/123) had a detectable HBV viral load, with 7.32% having an HBV VL >2000 IU/mL which has previously been linked to an increased risk of HBV related complications. Sequencing results showed that 10 samples had lamivudine resistance, however, no tenofovir resistance was detected. Three samples had immune escape mutations, two caused by the HBsAg mutations E164D and I195M and one by the immune-associated escape mutations N131T and D144A. The results from the study show that patients with HIV/HBV co-infection need to be monitored more closely in South Africa regarding HBV treatment response. The extensive use of lamivudine for HIV treatment in South Africa can be a driver of immune escape and further research needs to be done to determine the possible public health impact.
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Keywords
Dissertation (M.Sc. (Medical Microbiology and Virology))--University of the Free State, 2021, HIV/HBV co-infection, HIV viral load, HBV viral load, Comparison, DOH guidelines, HBV treatment, HIV/HBV treatment, Drug resistance, Lamivudine, Tenofovir
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