Perinatal Hepatitis B Virus Infection: Screening of Pregnant Women and Protection of the Infant

several reasons. First, nearly all infants who acquire the infection from their mothers in the newborn period will become chronic carriers of the virus (1). Second, al-though carriers usually remain healthy throughout child-hood and early adult life, many (especially men) will eventually develop cirrhosis of the liver or hepatocellular carcinoma (2). Third, perinatal infection and the subse-quent development of the chronic carrier state in these infants are largely preventable through immunoprophy-laxis (3-8). Prophylaxis against perinatal hepatitis B virus infec-tion is possible because most infants acquire their infec-tions not in utero but at or near the time of delivery (1). Transmission of the virus in the perinatal period provides an opportunity for postexposure prophylaxis, and three options are available: hepatitis B immunoglobulin, hepa-titis B vaccine, or a combination of the two. Because use of either agent alone has generally provided up to 7 5 % protective efficacy (3-6, 9) , improved efficacy was sought through their combined use. Theoretically, the passively administered antibody in immunoglobulin provides im-mediate protection until the infant develops an active im-mune response to the vaccine and achieves long-term protection. Combined use has proved to be more effective than either hepatitis B immunoglobulin or vaccine alone. Among the highest-risk infants (those whose mothers are positive for both hepatitis B surface and e antigens), pas-sive-active prophylaxis reduces the carrier rate from a