Hep B Vaccine
Definition And Composition
- Active substance comprises viral surface protein hepatitis B surface antigen.
- Produced via recombinant DNA technology in yeast.
- Adsorbed onto aluminum salts serving as adjuvant.
- Available in monovalent formulation or combined in pentavalent and hexavalent vaccines.
Dosage And Administration Details
| Parameter | Specification |
|---|---|
| Dose | 0.5 mL (10 ยตg) for individuals under 18 years; 1.0 mL (20 ยตg) for adults. |
| Route | Intramuscular injection. |
| Site | Anterolateral thigh in infants and children under 3 years; deltoid in older children and adults. |
| Storage | 2-8 degrees Celsius; freezing destroys vaccine potency. |
- Avoid gluteal region to prevent low immunogenicity and inadequate response.
Immunization Schedule
- Universal Immunization Program recommends zero dose at birth followed by primary doses at 6, 10, and 14 weeks.
- Birth dose ideally administered within 24 hours to effectively prevent perinatal and horizontal transmission.
- Catch-up schedule requires three doses administered at 0, 1, and 6 months.
Efficacy And Protection
- Protective antibody concentration established at >10 mIU/mL.
- Elicits long-term immunity exceeding 22 years.
- Routine booster doses remain unnecessary for healthy individuals due to robust immune memory.
- Booster vaccination indicated if antibody titers drop below 10 mIU/mL in hemodialysis or immunocompromised patients.
Management In Special Situations
Mother Hepatitis B Surface Antigen Positive
- Administer Hepatitis B vaccine and Hepatitis B immunoglobulin within 12 hours of birth.
- Administer products at separate anatomical injection sites.
- Follow with three additional vaccine doses at 6, 10, and 14 weeks.
- Perform post-vaccination serology testing at 9-12 months of age to confirm immunity.
Preterm And Low Birth Weight Infants (<2000 Grams)
- Mother antigen negative: Administer birth dose, but exclude from primary series count; administer three regular doses according to national schedule.
- Mother antigen positive or unknown: Administer vaccine and immunoglobulin within 12 hours of birth.
Nonresponders
- Defined as recipients failing to develop antibody titers >10 mIU/mL after primary series.
- Mandates testing for surface antigen to rule out chronic underlying infection.
- Requires administration of a second three-dose series and subsequent retesting.
Post-Exposure Prophylaxis
| Source Status | Unvaccinated Personnel | Fully Vaccinated Responder |
|---|---|---|
| Antigen Positive | Immunoglobulin x 1 and begin vaccine series | No treatment |
| Antigen Negative | Begin vaccine series | No treatment |
- Immunoglobulin dose measures 0.06 mL/kg administered intramuscularly.
Adverse Events And Contraindications
- Minor adverse reactions include local soreness, fever, and fatigue.
- Absolute contraindication involves severe allergic reaction or anaphylaxis to previous dose or yeast component.
- Pregnancy and lactation represent safe periods for administration and are not contraindications.