Method: A cross sectional study was done in 106 infants from HBsAg-positive or HBeAg-positive mothers in the Binh Duong Obs & Gyn, Pediatric Hospital 1 from January 2016 to Agust 2018. All the infants were given 1 dose of HBIG at birth and 4 doses of HB vaccine according to the National Immunization Program / Expanded Program on Immunization (at birth, 2, 3, and 4 months of age).