Seroprevalence of Hepatitis B virus infection and seroprotection of Hepatitis B vaccine among children in Jimma Town, South-West Ethiopia

ABSTRACT

Background: Hepatitis B virus is the leading cause of viral hepatitis and about 240 million people worldwide are chronic carriers. The virus is reported to be widely prevalent in Ethiopia and routine vaccination of children has been initiated in the country recently. We assessed the seroprevalence of HBV infection and seroprotection of HBV vaccine among children in Jimma. Methods: A community-based cross-sectional study was conducted among 900 children who were 5-9 years of age between June and December 2016. A simple random sampling technique was employed to recruit study participants by proportional allocation into different Kebeles of Jimma. Data were collected using pretested questionnaire.3-5ml of blood sample was collected from each child and it was tested for HBsAg, anti-HBc, and anti-HBs using ELISA (Bio-rad, Monolisa, Lacquote, France). Data were analyzed using chi-square and logistic regression analysis. Result: HBsAg and anti-HBc prevalence among all participants was 3.5% and 3.8%, respectively. The prevalence of HBsAg among vaccinated and non-vaccinated children was 2.1% and 7.0% whereas anti-HBc positivity was 1.1% and 6.2%, respectively. It was also found that 58.4% of vaccinated children maintained a protective level of HB surface antibodies which is defined as ≥ 10 mIU/ml anti-HBs. While 1.8%(4/222) vaccinated children with protective anti-HBs levels were positive for hepatitis B core antibody, none of the vaccinated children with non-protective anti-HBs levels were positive for hepatitis B core antibody. Multi-variable logistic regression revealed that lack of vaccination (AOR =2.788, P < 0.029), children who were born at home (AOR= 3.211, P < 0.009), and children who had a history of hospital admission (AOR= 7.122, P <0.001) were more likely to be HBV surface antigen positive. Conclusion: The seroprevalence of hepatitis B infection is high among children who have not received HBV vaccination. Hepatitis B vaccine has contributed to the reduction of the infection in this endemic area, though further efforts are required to improve timely vaccination and its coverage. The prevalence of protective anti-HBs is low among fully vaccinated children, hence, it is better to include the monovalent birth dose of the vaccine and conduct further studies to evaluate underlining causes for the waning of serum anti-HBs level