BackgroundHepatitis B virus (HBV) can be transmitted by blood donors and organ donors who are positive for antibody to HBV core antigen (anti-HBc) but negative for all other HBV markers. Therefore, we evaluated the risk of infection for babies of mothers with this serostatus MethodsA total of 2365 HBV surface antigen (HBsAg)–negative pregnant women were included in the study and screened for anti-HBc. Blood samples for screening were collected 1 day before or after delivery. Infants of mothers with positive anti-HBc test results were tested 3–4 months after birth ResultsOf 2365 mothers, 147 (6.2%) were anti-HBc positive. Follow-up tests were performed using samples from 105 children. Samples were tested for all HBV markers, including HBV DNA, which was evaluated using a highly sensitive polymerase chain reaction assay (Taq PCR). Seven children (6.6%) had markers of HBV infection; the Taq PCR detected HBV DNA in 5, and HBsAg was detected in the other 2 ConclusionsThis study shows that HBV can be transmitted perinatally even in the absence of HBsAg. None of the children developed chronic HBV infection. Further studies must determine whether routine immunization of infants at the age of 3 months gives enough protection against HBV infection or whether screening of pregnant women for HBV should be extended, with immunization of their newborns beginning immediately after birth