Prevalence and Associated Factors of HBV Infections among HIV-Infected HAART Receiving Mothers and their Exposed Infants in Nairobi, Kenya

Abstract

Mother-to-child transmission (MTCT) of Hepatitis B virus (HBV) is responsible for more than one third of chronic HBV infections worldwide. Antiretroviral therapy (ART) naïve HBV/HIV co-infected mothers have a high tendency of transmitting the two viruses. This study aimed to determine prevalence & predisposing factors of HBV infections among HAART-receiving HIV-infected mothers and their exposed infants. A structured questionnaire was used to capture socio-demographic data and factors associated with HBV infections. As 4_ml sample of paired whole blood obtained from HIV positive mothers & their exposed infants was analyzed for Hepatitis B surface antigen (HBsAg) using both rapid and Enzyme-linked immuno sorbent assay (ELISA) tests. HBsAg positive samples were further screened for HBV envelope antigen (HBeAg) using ELISA. HBsAg positive samples with both ELISA and rapid tests were subjected to a nested Polymerase chain reaction (PCR) targeting the preS1 region. A total of 534 HIV-infected mothers - infant pairs were recruited. Mean age of mothers was 31.2 years (SD 5.4 years) and infants’ median age of 6 months (IQR 3-10 months). 502 (94%) of the mothers were taking TDF/3TC/ NVP and 32(6%) were on AZT/3TC/NVP or EFV. 19 of 534 (3.6%) mothers were HBV positive by both HBsAg rapid and ELISA tests. All 19 HBsAg positive samples tested HBeAg negative. 12 of the 19 HBsAg positive samples also tested positive on PCR targeting the preS1 gene. All infants’ samples tested HBV negative with all tests. History of dental surgery was associated with increased rate of HBV infection (OR 3.3 (95% CI 1.1-9.6). In this population of HIV-infected pregnant mothers, our observations suggest that the HAART regimen received by them may have prevented vertical transmission of HBV infections to exposed infants.