-1INTRODUCTION: PROBLEM STATEMENT Hepatitis B is a global problem Approximately 30% of the world’s population, about billion people, have serological evidence of infection with hepatitis B virus (HBV) It is estimated that 350 million of them have chronic HBV infection, about a million of whom die each year from chronic liver disease, including cirrhosis and liver cancer In areas of high endemicity, most of infection are acquired from mother to baby transmission (perinatal) Perinatal transmission usually happens at the time of birth, in utero or shortly after delivery The risk of chronic HBV infection is approximate range 70-90% in children born to mothers with HBeAg(+), and about 20% in those whose mothers are HBeAg-negative In 2006, after information of complicaitons of the first doses of injection of Hepatitis B vaccine in Ho Chi Minh City and Ha Tinh province, the coverage rate of the first doses of Hepatitis B vaccine in newborns (10 mUI/ml Failure vaccination: HBsAg(+); HBsAg(-) and anti-HBs