Date of Award

2020

Document Type

Dissertation

Degree Name

Master of Medicine (MMed)

First Supervisor/Advisor

Dr Reena Shah

Second Supervisor/Advisor

Dr Jasmit Shah

Third Supervisor/Advisor

Dr Rodney Adam

Department

Internal Medicine (East Africa)

Abstract

Background: Human immunodeficiency virus (HIV) and hepatitis B virus (HBV) are endemic to sub-Saharan Africa (SSA) with co-infection being common. Infection with HIV is a risk factor for occult hepatitis B virus infection (OBI), defined as presence of HBV deoxyribonucleic acid (DNA) in the absence of hepatitis B surface antigen (HBsAg). Occult hepatitis B virus infection is further classified based on HBV DNA level as true (/mL) or false (≥200 IU/mL). Presence of OBI is associated with development of liver cirrhosis and hepatocellular carcinoma (HCC).

Objectives: The primary outcome was to determine the prevalence of OBI in anti-retroviral therapy (ART) naïve HIV infected adults. Secondary outcomes included defining the proportion of true and false OBI, the serologic and clinico-demographic profiles of OBI and the exposure to HBV in ART naïve HIV patients.

Methods: A cross sectional study carried was out at three sites in and around Nairobi, Kenya where HIV infected ART naïve adults were enrolled and demographic data collected. Blood samples were assayed for HBsAg, HBV DNA, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and antibodies to hepatitis B surface antigen (anti-HBs) and hepatitis B core antigen (anti- HBc). Data on CD4 count, HIV viral load, and platelet count were obtained from medical records.

Results: From March 2019 to April 2020, 208 ART naïve patients were enrolled; 113 (54%) were female, mean age was 38.7 ± 10.6 years, 199 (95.7%) did not report prior HBV vaccination, 196 (94.2%) were HBsAg negative and 119 (57.2%) had no detectable HBV marker. Of the 196 HBsAg negative patients, 58 (29.6%) had previous HBV infection (anti-HBc positive) and 11 (5.6%) had detectable HBV DNA, implying OBI. Of the 11 patients with OBI, 10 (90.9%) had true OBI and 11 (100%) were anti-HBc positive. Patients with OBI comprised 19.0% of HBsAg negative, anti-HBc positive patients. There was no difference in clinical and demographic characteristics between the overt HBV, OBI and HBV negative populations.

Conclusions: This was the first study on OBI in Kenya. The lower OBI prevalence compared to other Sub-Saharan African countries could be attributed to lower HBV exposure. Most patients were HBV unexposed and unimmunized, outlining the need to implement guideline recommended immunization strategies for this population virus (HIV) and hepatitis B virus (HBV) are endemic to sub-Saharan Africa (SSA) with co-infection being common. Infection with HIV is a risk factor for occult hepatitis B virus infection (OBI), defined as presence of HBV deoxyribonucleic acid (DNA) in the absence of hepatitis B surface antigen (HBsAg). Occult hepatitis B virus infection is further classified based on HBV DNA level as true (/mL) or false (≥200 IU/mL). Presence of OBI is associated with development of liver cirrhosis and hepatocellular carcinoma (HCC).

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