Routine vaccination

• 3-dose series at age 0, 1–2, 6–18 months (use monovalent HepB vaccine for doses administered before age 6 weeks)
  -Birth weight ≥2,000 grams: 1 dose within 24 hours of birth if medically stable
  -Birth weight < 2,000 grams: 1 dose at chronological age 1 month or hospital discharge (whichever is earlier and even if weight is still < 2,000 grams).

• Infants who did not receive a birth dose should begin the series as soon as possible (see Table 2 for minimum intervals).

• Administration of 4 doses is permitted when a combination vaccine containing HepB is used after the birth dose.

• Minimum intervals: when 4 doses are administered, substitute “dose 4” for “dose 3” in these calculations

• Final (3rd or 4th) dose: age 6–18 months (minimum age 24 weeks)

• Mother is HBsAg-positive
  -Birth dose (monovalent HepB vaccine only): administer HepB vaccine and hepatitis B immune globulin (HBIG) (in separate limbs) within 12 hours of birth, regardless of birth weight.
  -Birth weight < 2000 grams: administer 3 additional doses of HepB vaccine beginning at age 1 month (total of 4 doses)
  -Final (3rd or 4th) dose: administer at age 6 months (minimum age 24 weeks)
  -Test for HBsAg and anti-HBs at age 9–12 months. If HepB series is delayed, test 1–2 months after final dose. Do not test before age 9 months.

• Mother is HBsAg-unknown
  If other evidence suggestive of maternal hepatitis B infection exists (e.g., presence of HBV DNA, HBeAg-positive, or mother known to have chronic hepatitis B infection), manage infant as if mother is HBsAg-positive
  -Birth dose (monovalent HepB vaccine only):
  - Birth weight ≥2,000 grams: administer HepB vaccine within 12 hours of birth. Determine mother’s HBsAg status as soon as possible. If mother is determined to be HBsAg-positive, administer HBIG as soon as possible (in separate limb), but no later than 7 days of age.
  - Birth weight < 2,000 grams: administer HepB vaccine and HBIG (in separate limbs) within 12 hours of birth. Administer 3 additional doses of HepB vaccine beginning at age 1 month (total of 4 doses)
  -Final (3rd or 4th) dose: administer at age 6 months (minimum age 24 weeks)
  -If mother is determined to be HBsAg-positive or if status remains unknown, test for HBsAg and anti-HBs at age 9–12 months. If HepB series is delayed, test 1–2 months after final dose. Do not test before age 9 months.

Catch-up vaccination

• Unvaccinated persons should complete a 3-dose series at 0, 1–2, 6 months.

• Adolescents age 11–15 years may use an alternative 2-dose schedule with at least 4 months between doses.

• Adolescents age 18 years or older may receive:
  - HepB vaccine 2-dose series at least 4 weeks apart
  - HepB vaccine 3-dose series at 0, 1, and 6 months

Special situations

• Revaccination is not generally recommended for persons with a normal immune status who were vaccinated as infants, children, adolescents, or adults.

• Post-vaccination serology testing and revaccination: (if anti-HBs < 10mlU/mL) is recommended for certain populations, including:
  -Infants born to HBsAg-positive mothers
  -Persons who are predialysis or on maintenance dialysis
  -Other immunocompromised persons