Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 12 4 2013 12 15 352 360 EN Azam Ghaziasadi Hepatitis B Molecular Laboratory, Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Seyed Moayed Alavian Baqiyatallah University of Medical Sciences, Baqiyatallah Research Centre for Gastroenterology and Liver Disease, Tehran, Iran Mahdi Norouzi Hepatitis B Molecular Laboratory, Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Zeinab Fazeli Hepatitis B Molecular Laboratory, Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Seyed Mohammad Jazayeri Hepatitis B Molecular Laboratory, Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran 2015 10 16 Hepatitis B vaccination is safe and effective, although breakthrough infection occasionally occurs in those who receive the vaccine and hepatitis B immunoglobulin (HBIg) prophylaxis. Sequence variation in their antigenic regions is one of the most powerful strategies that are used by viruses to escape recognition by B and T cell-mediated immune responses. The aim of this study was to explore the mutational profile of HBV in vertical transmission. Six HBsAg-positive mothers and their children who developed HBV infection despite immunoprophylaxis were enrolled. After extraction of HBV DNA from sera, the full HBV genome or surface gene was amplified by Gunther and hemi-nested PCR, respectively. After sequencing, the mutational analysis on paired samples between mothers and children were carried out and compared. Different mutations were found in four children; at least, one arose in functional and/or immune epitope activities. Of 30 amino acid changes, 11 (36.6%) were located within the known HBV immune epitopes. In three children, mutations occurred within the “a” determinant region, one mutation (B2) was identical to the mother of patient, an indication of vertical transmission. The other two (B4 and B5) were considered as vaccine escape mutations. Three children harbored wild-type HBsAg, similar to their mothers. Regarding transmission in infected children, the immunoprophylaxis had no effect and failure of vaccination was observed in 2 isolates. These   findings   emphasized   the   need   for   an   alternative   regimen,   such   as   the administration of boosters or a more effective HBV vaccine for high-risk children who are born to HBsAg-positive mothers. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/492 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/492/552