Prevalence and Molecular Characterization of Hepatitis B Virus Infection in HIV Infected Patients on Antiretroviral Therapy in Nairobi, Kenya

Abstract

Hepatitis B Virus and Human Immunodeficiency Virus infections are significant universal health challenges. Simultaneous infection with these two viruses can cause severe and progressive liver disease, liver cancer and mortality. These challenges demand continuous surveillance for hepatitis B infection among the Human Immunodeficiency Virus-positive population to guide the prevention and treatment of patients. In Kenya, where the prevalence of HIV/HBV co-infection is on the rise, there is an urgent need to investigate the molecular profiles of hepatitis B virus strains and surface antigen mutants, especially those that are circulating among individuals co-infected with Human Immunodeficiency Virus. This study focused on understanding the molecular characteristics of hepatitis B virus among Human Immunodeficiency Virus co-infected patients in Nairobi County. A laboratory-based cross-sectional study was carried out on specimens collected from 10 sub-county health facilities in Nairobi namely; Langata, Dagoretti, Starehe, Ruaraka, Kasarani, Embakasi West, Kamukunji, Embakasi East, Westland, and Makadara. A total of 870 HIV-positive specimens were screened for hepatitis B surface antigen using Enzyme-Linked Immunosorbent Assay. Of these, 78 (8.97%) tested positive and were subjected to polymerase chain reaction followed by nested PCR. The amplicons were sequenced and the HBV sequences generated were analyzed to identify HBV genotypes and possible S gene mutations. Of the 78 samples that tested positive with ELISA, 38 (48.72%) had detectable HBV DNA viral copies; 34 that had HBV DNA counts above 1000 copies/ml were genotyped. Twenty-six (76.47%) samples were identified as HBV genotype D and 8 (23.53%) as genotype A. Some escape mutations associated with failure of diagnosis (R122K, N143S, and V168A) and with vaccine escape (T114S, Y134F, G145V, N146K, T148P E164G) were detected in varying frequencies in the population. This study confirms that the prevalence of HIV/HBV coinfection in Nairobi County is 8.97% (95% CI 7.24%-11.06%). This is significant and for that reason deserves targeted public health approaches. The study also found that HBV genotypes A and D are the most common genotypes circulating among HIV co-infected patients in Kenya. Some escape mutations associated with HBV diagnosis failure, vaccine escape and immunoglobulin therapy were also observed and this can be crucial in vaccine optimization and diagnostic tools development. Subsequent studies should focalize on establishing the clinical consequence of the various HBV strains and variations found in this population