What is the recommended Hepatitis B (HBV) vaccine dosage and interval for a general adult population?

Hepatitis B Vaccine Adult Dosage and Interval

For adults ≥20 years, administer hepatitis B vaccine as a 3-dose series at 0,1, and 6 months using either Recombivax HB (10 μg per dose) or Engerix-B (20 μg per dose), or alternatively use the 2-dose Heplisav-B regimen (20 μg at 0 and 1 month) for improved compliance and higher seroprotection rates. 1, 2

Standard Dosing Regimens

Three-Dose Schedule (Traditional)

• Engerix-B: 20 μg (1.0 mL) administered intramuscularly at 0,1, and 6 months 2
• Recombivax HB: 10 μg (1.0 mL) administered intramuscularly at 0,1, and 6 months 1
• PreHevbrio: 10 μg (1.0 mL) administered intramuscularly at 0,1, and 6 months 1
• This schedule produces protective antibody response (≥10 mIU/mL) in >90% of healthy adults aged <40 years after completing the series 3

Two-Dose Schedule (Newer Option)

• Heplisav-B: 20 μg (0.5 mL) administered intramuscularly at 0 and 1 month 1
• This regimen demonstrates superior seroprotection rates (approximately 90%) compared to traditional 3-dose schedules (70.5%-90.2%) 4
• Major advantage: Better compliance due to fewer doses and shorter completion time 1

Expected Immune Response

The 3-dose series produces a stepwise antibody response in healthy adults <40 years 3:

• After dose 1: 30-55% seroprotection
• After dose 2: 75% seroprotection
• After dose 3: >90% seroprotection

Critical caveat: Response rates decline with age—by age 60 years, only 75% achieve protective antibody levels even after completing the full series 3. Other factors reducing vaccine response include smoking, obesity, and immunosuppression 3.

Alternative Schedules

Accelerated Schedule (For High-Risk Exposures)

• Administer at 0,1,2, and 12 months for individuals requiring rapid protection 1, 2
• This provides earlier seroprotection but requires a fourth dose at 12 months for optimal long-term protection 1, 2
• The fourth dose produces substantially higher antibody titers (GMT of 9,163 mIU/mL at month 13) compared to the 3-dose schedule 2

Flexible Timing

• Alternative intervals of 0,1, and 4 months OR 0,2, and 4 months produce similar seroprotection rates to the standard 0,1,6-month schedule 3
• Minimum acceptable intervals: 4 weeks between doses 1 and 2; 8 weeks between doses 2 and 3; 16 weeks between doses 1 and 3 3, 1

Special Populations

Hemodialysis and Immunocompromised Patients

• Recombivax HB: 40 μg (1.0 mL) per dose in a 3-dose schedule 1
• Engerix-B: 40 μg (2.0 mL) per dose in a 4-dose schedule at 0,1,2, and 6 months 1, 2
• These patients require higher doses because standard dosing produces inadequate response—only ~50% achieve protective titers with standard dosing 2
• Annual antibody testing recommended; administer 40 μg booster when anti-HBs falls below 10 mIU/mL 2

Pregnant Women

• Only use Engerix-B, Recombivax HB, or Twinrix 1, 5
• Do not use Heplisav-B or PreHevbrio—insufficient safety data in pregnancy 1, 5

Administration Technique

• Route: Intramuscular injection in the deltoid muscle 2
• Never inject in the gluteal region—this produces suboptimal immune response 2
• Subcutaneous administration may be used for patients at hemorrhage risk (e.g., hemophiliacs), but expect lower antibody titers and increased local reactions 2

Managing Interrupted Series

Critical principle: Never restart the vaccination series if interrupted 1, 5:

• Simply continue where you left off 1, 5
• Ensure the second and third doses are separated by ≥8 weeks 1, 5
• The final dose must be administered at least 16 weeks after the first dose 1, 5
• Doses administered ≤4 days before the minimum interval are considered valid 1

Common Pitfalls to Avoid

• Do not restart interrupted series—there is no maximum interval between doses; just continue the schedule 1, 5
• Do not use Heplisav-B or PreHevbrio in pregnant women, hemodialysis patients, or children 1, 5
• Do not inject in the gluteal region in adults—this consistently produces suboptimal response 2
• Do not assume all adults respond equally—age >40 years significantly reduces vaccine efficacy, requiring consideration of post-vaccination antibody testing in high-risk occupations 3
• Do not use intradermal administration routinely—while some studies show immunogenicity with 2 μg intradermal dosing, this route produces significantly lower seroconversion rates (78.1% vs 97.2%) and antibody titers compared to intramuscular administration 6

Post-Vaccination Testing

Routine serologic testing is not necessary for most adults 3. However, testing for anti-HBs 1-2 months after series completion is recommended for 3, 4:

• Healthcare and public safety workers
• Chronic hemodialysis patients
• HIV-infected and other immunocompromised persons
• Sex or needle-sharing partners of HBsAg-positive persons

Protective level: Anti-HBs ≥10 mIU/mL 3, 4