Baseline Serological Markers of Hepatitis B Virus Co-Infection in the Development of Antiretroviral Therapy for Africa (DART) Population of Human Immuno Deficiency Virus Infected Patients

Abstract

Hepatitis B virus (HBV) seroprevalence and serology profiles were retrospectively determined for 957 individuals in the Development of Antiretroviral Therapy for Africa (DART), human immunodeficiency virus (HIV) infected population. Baseline HBV serology markers were tested for and samples identified for viral load test in the HBV sub study investigating development of HBV Tenofovir (TDF)/lamivudine (3TC) resistance in HIV-1 positive treatment naïve individuals initiating TDF/3TC combination therapy as part of HAART. The patients received TDF/3TC combination therapy as part of HAART and samples were taken at baseline and at 4, 12, 24 and 48 weeks and every 48 weeks thereafter until last visit, up to 6 years. All samples were tested for anti-HBc and HBsAg with further testing for anti-HBs and HBe markers in anti-HBc+/HBsAg- and anti-HBc+/HBsAg+samples respectively using enzyme immune assays. In this population 164 patients were HBsAg positive giving a 17.1 % HBsAg seroprevalence (males 18.3 %, females 15.8 %). Five hundred and thirty (530) samples or 55.4 % were positive for the anti-HBc marker. One hundred and thirty five patients had isolated anti-HBc and will be tested for occult HBV, 103 were anti-HBc+/HBsAg+/HBe marker + and were identified for viral load tests on baseline and follow up samples to investigate HBV TDF/3TC resistance evidenced by viral rebound. The results infer a high prevalence of HBV co-infection in HIV infected individuals in Zimbabwe. HIV positive individuals are at risk of co-infection with HBV because of the shared routes of infection of HIV and HBV. This is supported by the high level of exposure to HBV evidenced by 55.4 % anti-HBc seroprevalence in the DART cohort. There was evidence of active hepatitis, 103 individuals with positive HBe markers, and HBV DNA tests can be done on these baseline and follow up samples to monitor the efficacy of TDF/3TC combination therapy in suppressing viral rebound. Viral load tests can also be done on 135 samples with isolated anti-HBc to determine the prevalence of occult HBV in this cohort. KEY WORDS: HBV seroprevalence, HIV co-infection, HBV tenofovir/lamivudine resistance iii ACKNOWLEDGEMENTS This thesis was made possible through the support of the Development of Antiretroviral therapy for Africa (DART) study group who provided the samples. I am grateful to Dr Chirara, Prof Robertson and other members of the DART study for allowing me to contribute to the DART HBV sub study through this project. Dr Chirara and Prof Robertson provided me with invaluable support, guidance and mentorship throughout the project. The University of Zimbabwe department of medical microbiology virology laboratory members provided me with the necessary training to do this work and opened the doors of their laboratory for me to work in, for that I am most grateful. Thank you Ms Berejena and Mr T. Mamvura. I also thank my classmates in the MSc medical microbiology program for the shared experiences throughout this program.