Urusa TheppisaiChalermsri ThanuntasethPimol ChiewsilpPraput SiripoonyaMahidol University2018-06-142018-06-141989-01-01Asia‐Oceania Journal of Obstetrics and Gynaecology. Vol.15, No.2 (1989), 111-11514470756038923282-s2.0-0024678950https://repository.li.mahidol.ac.th/handle/20.500.14594/15840Immunoprophylaxis of HBV infection using 3 doses (10 μg) of plasma derived HBV vaccine were given to 49 newborn infants of e‐antigen negative HBs Ag carrier mothers at birth, one and 6 months of age. The protective efficacy rate was 100% during first 2 years. At 3 years of age, HBs Ag carrier was 2.63% and 89.48% of infants had anti‐HBs above the protective level. Ten point fifty‐two percent of total infants had anti‐HBs level below 10 mIU/ml and 21.05% had anti‐HBs level between 10–100 mIU/ml. Most infants who had the maximal level of antibody below 100 mIU/ml had lost all antibody within 3 years. The loss of antibody was closely related to the maximal anti‐HBs titer (one year of age) which is highly predictive indicator of the longevity of anti‐HBs. © 1989 Japanese Society of Obstetrics and GynaecologyMahidol UniversityMedicineArticleSCOPUS10.1111/j.1447-0756.1989.tb00162.x