The hepatitis B vaccine was firstintroduced in 1981. Initially, it was prepared as an inactivatedvaccine from the plasma of carefully screened human, hightitercarriers/donors. In 1986, the recombinant DNA (rDNA)vaccine (Engerix B, Recombivax) was introduced to the market.The rDNA vaccine contains only viral subunits and maybe used with hepatitis B immune globulin in a postexposuresetting to boost the ability of the host to resist the infection. Inadults, three doses should be given, at 0, 1, and 6 months. Inchildren, the vaccine is given at birth, 1 month, and 9 months.Administration may be delayed in premature infants whoseimmune systems are not fully developed. If not immunized atbirth, a child should receive three doses by 18 months. If themother tests positive for hepatitis B, the vaccine plus the immuneglobulin must be given at or shortly after birth. The vaccineis 95% effective and is typically without side effects.Several high-risk groups have been identified: healthcareworkers, student healthcare workers, people living in highriskenvironments, and dentists. They should receive a threedosecourse of the vaccine. In most other cases, a physiciancan judge whether a patient is at high risk or not. Side effectsof the vaccine are minor.
