Sero-prevalence of hepatitis b virus infection and seroprotection of hepatitis b vaccine among children in jimma town, southwest Ethiopia

Abstract

Background: Hepatitis B virus (HBV) is the leading cause of viral hepatitis and about 240 million people worldwide are chronic carrier. The virus was known widely prevalent in Ethiopia and has several serious complications. The vaccines used for the virus have an outstanding record of safety and effectiveness; however, about 10% of the vaccinees still remain susceptible to HBV, especially those vaccinees were from infected mothers. The disease burden among children and sero-protection of HBV vaccine is mainly unknown in the study area. Therefore, this study assessed the sero-prevalence of HBV infection and sero-protection of HBV vaccine among children in Jimma town. Methods: Community based cross-sectional study was conducted among 900 children of 5 to 9 years of age from June to December, 2016. Simple random sampling technique was employed to recruit study participants by proportional allocations into different Kebeles of Jimma town. Data was collected by using pretested questionnaire and about 3-5ml of blood sample was collected and tested for HBsAg, anti-HBc and anti-HBs by using ELISA (Bio-rad, Monolisa, Lacquote, France) technique. Data were analysed using chi-square and logistic regression test. Result: This study revealed that the HBsAg and anti-HBc prevalence among all participants were 3.5% and 3.8%, respectively. The prevalence of HBsAg among vaccinated and nonvaccinated was 2.1% and 7.0% respectively. Anti-HBc positivity was 1.1% and 6.2% among vaccinated and non-vaccinated children. The sero-protection of HBV vaccine among fully vaccinated children showed that 71.6% against chronic HBsAg carriage whereas 83.4% against total HBV infection. It was also found that 58.4% of vaccinated children retained protective level of HB surface antibodies, ≥ 10 mIU/ml with the mean of 50 mIU/ml. Multiple logistic regression revealed that lack of vaccination (AOR =2.788, P < 0.029), child who were born at home (AOR= 3.211, P < 0.009) and hospital admission (AOR= 7.122, P <0.001) were the significant predicting variables for HBsAg positivity Conclusion: The sero-prevalence of hepatitis B infection is high among children who have not been vaccinated for the virus. 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 cuases for wanning of serum anti-HBs level.