At what age should my son receive the Hepatitis B (Hep B) vaccine?

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Hepatitis B Vaccination Schedule for Infants

Your son should receive his first dose of hepatitis B vaccine at birth (within 12 hours), followed by doses at 1-2 months and 6 months of age. 1, 2

Standard Vaccination Schedule

The recommended hepatitis B vaccination schedule for infants consists of:

  • First dose: At birth (within 12 hours of life)
  • Second dose: At 1-2 months of age
  • Third dose: At 6 months of age

This three-dose series provides excellent protection against hepatitis B infection, with 95-100% of infants achieving protective antibody levels after completing the series 3.

Special Considerations Based on Maternal Status

The vaccination schedule may be modified based on the mother's hepatitis B surface antigen (HBsAg) status:

If mother is HBsAg-positive:

  • First dose of hepatitis B vaccine AND hepatitis B immune globulin (HBIG) within 12 hours of birth
  • Second dose at 1-2 months
  • Third dose at 6 months 1, 2

If mother's HBsAg status is unknown:

  • First dose of hepatitis B vaccine within 12 hours of birth
  • Test mother's blood for HBsAg as soon as possible
  • If mother tests positive, give HBIG to infant as soon as possible (no later than 7 days of age)
  • Complete vaccine series with doses at 1-2 months and 6 months 1

If mother is HBsAg-negative:

  • First dose at birth (within 12 hours is still recommended)
  • Second dose at 1-2 months
  • Third dose at 6 months 1

Low Birth Weight Considerations

For infants weighing less than 2,000 grams at birth:

  • If mother is HBsAg-negative: First dose at hospital discharge or 1 month of age
  • If mother is HBsAg-positive: Four-dose schedule (birth, 1 month, 2-3 months, and 6 months) 1

Important Points to Remember

  • Only monovalent hepatitis B vaccine (not combination vaccines) should be used for the birth dose 2
  • Combination vaccines containing hepatitis B (like Pediarix) may be used for doses after the birth dose, typically at 2,4, and 6 months 1
  • The final dose in the vaccine series should not be administered before 24 weeks (6 months) of age 1
  • Both available recombinant hepatitis B vaccines in the US (Engerix-B and Recombivax HB) are safe and effective, with 99% of infants achieving protective antibody levels after the complete series 4

Long-term Protection

Studies have shown that the three-dose hepatitis B vaccination series provides long-lasting protection. Most infections that occur in vaccinated children happen early and result from prenatal infection, initial non-response to the vaccine, or delay in the initial dose—not from waning immunity 5. Therefore, booster doses are not routinely recommended for children who complete the standard vaccination series.

The timely administration of the birth dose is particularly important as it has been shown to significantly reduce the risk of infection, especially for infants born to HBsAg-positive mothers 6, 5.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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