vaccine failure in the neonat is rare but dose occur(fewer than 10% of prophylaxed neonates), and many be accounted for by transplacental transmission before birth. Follow up testing of the neonate should be performed to confirm vaccination effectiveness. testing should be performed for HBs Ag to detect vaccine failures, antiHBs to confirm a successful vaccine response and anti HBc total to determine if the anti HBs response was due to vaccination or resolution of natural infection.