Serological positive markers of hepatitis B virus in femoral venous blood or umbilical cord blood should not be evidence of in-utero infection among neonates

Background Maternal-infant transmission of hepatitis B virus(HBV) occurs even after passive-active immunization. Some scholars speculate that in-utero infection may be the main cause of immunoprophylaxis failure. However, there is a lack of evidence about the possible occurrence periods of perinatal transmission.