Hepatitis B must now be considered a preventable disease because acute infection can be effectively eliminated by either passive immunization with hepatitis B immune globulin (HBIG) or active immunization.^32,167 In October 1997, the ACIP expanded its HBV vaccination recommendations to include all unvaccinated children aged 0 to 18 years, children in populations at high risk for HBV infection (eg, Native Alaskans, Pacific Islanders, and children who reside in households of first-generation immigrants from countries where HBV infection is moderately or highly endemic), previously unvaccinated children aged 11 to 12 years, older adolescents and adults in defined risk groups, and spouses or sexual partners of HBV-positive individuals.^16,168–171 Vaccination of susceptible persons will save medical costs for populations with annual HBV infection rates above 5%; vaccination may even be considered cost effective (or cost saving when indirect costs are included) for populations with infection rates as low as 1% to 2%.^172,173

Both passive and active immunization have a role in prevention of HBV transmission.^{16,32,167–170}

• The first dose of an HBV vaccine series and HBIG are frequently administered together for post-exposure prophylaxis. A single sexual exposure to an HBsAg-positive individual is an indication for HBIG if given within 2 weeks of exposure.

• Passive immune prophylaxis with HBIG, combined with the active vaccination series, may be appropriate in certain situations in which rapid development of antibody titers is desirable. For example, postexposure prophylaxis with immune globulin using the 2-dose series (administered 1 month apart) provides about 75% protection for acute exposure to blood containing HBsAg.

• Infants born to HBsAg-positive mothers should receive both immune globulin and HBV vaccine.

• Postexposure prophylaxis with HBIG (0.06 mL/kg) is indicated for exposure to blood containing HBsAg in a nonimmune individual. The first dose of an HBV vaccine series should be administered concomitantly, but at a different intramuscular site. If the person refuses the HBV vaccine, another dose of HBIG should be administered 1 month later. This postexposure prophylaxis is most effective if initiated within 1 week of exposure.

• Postexposure prophylaxis in patients with a sexual exposure consists of 1 dose of HBIG 0.06 mL/kg intramuscularly, preferably within 2 weeks of exposure.

• Hepatitis B immune globulin is always given intramuscularly for prophylaxis, never intravenously (except in liver transplant recipients).

Active vaccines. The previous plasma-derived HBV vaccine has been replaced by recombinant HBV vaccines (Engerix-B [SmithKline Beecham], Recombivax-HB [Merck & Co.]). The vaccines are highly effective and safe.

For Engerix-B, the usual dosing schedule is 0, 1, and 6 months; the alternate dosing schedule is 0, 1, 2, and 12 months.

• For children 0 to 10 years of age, the individual dose is 10 mg/0.5 mL. Adolescents 10 to 19 years of age may receive 10 mg/0.5 mL via the usual dosage schedule, or 20 mg/1.0 mL via either dosage schedule.

• Adults older than 19 years can receive 20 mg/1.0 mL via either dosage schedule.

• Hemodialysis patients can receive 40 mg/2.0 mL at 0, 1, 2, and 6 months.

The recommended dosing schedule for Recombivax-HB is as follows (all are 0, 1, and 6 month dosing schedules):

• 2.5 mg/0.5 mL for children 1 to 10 years of age;

• 5 mg/0.5 mL for children 11 to 19 years of age; and

• 10 mg/1.0 mL for adults 20 years of age and older.

• There is a special formulation for predialysis and hemodialysis patients, 40 mg/1.0 mL.