In our study, we will evaluate the immune status of HB virus in cohort of 100 children (Fully vaccinated, partially vaccinated and unvaccinated) aged from 1 to 18 years and asking about: Age, If the doses of HB vaccine completed or not, The interval between doses, Any complications after vaccination and Is there is any symptoms or sings of HB virus in unvaccinated children?.The consequences of failed or incomplete vaccination will be also evaluated in our study in an attempt to recommend therapy for chronic HBV infection.