Abstract:
Hepatitis B virus (HBV) infection is a major public health problem affecting approximately 360 million people globally. Mother-to-child transmission (MTCT) is responsible for more than one third of chronic HBV infections worldwide. Mothers who are co- infected with HBV/ Human Immunodeficiency virus (HIV) and are antiretroviral therapy (ART) naïve have a high tendency of transmitting the two viruses during pregnancy, delivery or postnatally. This study aimed to determine the prevalence and associated risk factors of HBV infections among Highly Active antiretroviral therapy (HAART) receiving HIV-infected mothers and their exposed infants at the Kenyatta National Hospital (KNH) in Kenya. Eligible mothers and their exposed infants were recruited from a cohort enrolled in a Prevention of mother to child transmission of HIV (PMTCT) program in KNH. A structured questionnaire was used to capture the socio-demographic data of the participants and information on associated factors to HBV infections. Four milliliters (ml) sample of paired whole blood were obtained from HIV positive mothers and their exposed infants. Whole blood was separated into plasma and stored at -80oC. HBV infection was determined using Euromedi Equipp (EME) rapid kit for Hepatitis B surface antigen (HBsAg) test and confirmed by a HBsAg Enzyme linked immune sorbent assay (ELISA). The HBsAg sero reactive samples were further screened for HBV envelope antigen (HBeAg) using ELISA (Accubiotech co.ltd). Samples which turned positive with ELISA and rapid tests were subjected to Polymerase-chain reaction (PCR) targeting the preS1 region using nested primers. HBV infection was presented as a proportion with 95% confidence interval and the associations tested using chi-square tests. A total of 534 HIV-infected mothers and their highly exposed infants were recruited. The mean age of the mothers was 31.2 years (SD 5.4 years) and the infants had a median of 6 months (IQR 3-10 months). Four hundred and thirty-three (81.1%) of the mothers were married, 272 (50.9%) having tertiary education and 113 (59.5%) were employed. One hundred and thirteen (21.2%) of the mothers were aware of HBV infection and HBV vaccination. Most of the mothers were currently receiving HAART with 502 (94%) of the mothers taking TDF/3TC/NVP and 32 (6%) on AZT/3TC/ NVP or AZT/3TC/EFV. Out of 534 mothers, 19(3.6%) were positive for HBV. All the 19 samples that gave positive HBsAg results tested negative for HBeAg. Out of the 19 samples that tested positive with ELISA, also gave positive results with PCR targeting the preS1 gene. All exposed infants tested negative for HBV with the HBsAg rapid, ELISA and PCR tests. History of dental surgery was associated with increased rate of HBV infection among the HIV-infected mothers (OR 3.3 (95% CI 1.1-9.6). In conclusion, the results of this study suggest that the HAART regimen received by the HIV infected pregnant mothers may have prevented vertical transmission of HBV infections to exposed infants.
