How many doses are required for the hepatitis B vaccine?

Hepatitis B Vaccine Dosing

The hepatitis B vaccine requires either 2 or 3 doses depending on the specific vaccine product used, with most traditional formulations requiring a 3-dose series (0,1, and 6 months) while Heplisav-B requires only 2 doses (0 and 1 month). 1, 2

Standard Adult Vaccination Schedules (Age ≥18 years)

Three-Dose Regimens

• Recombivax HB: 10 μg (1.0 mL) administered at 0,1, and 6 months 2
• Engerix-B: 20 μg (1.0 mL) administered at 0,1, and 6 months 2, 3
• PreHevbrio: 10 μg (1.0 mL) administered at 0,1, and 6 months 1, 2
• Twinrix (combined hepatitis A/B): Standard schedule of 0,1, and 6 months 2

Two-Dose Regimen

• Heplisav-B: 20 μg (0.5 mL) administered at 0 and 1 month (minimum 4-week interval) 1, 2
  • This is the only FDA-approved 2-dose hepatitis B vaccine for adults ≥18 years 2
  • Both doses must be Heplisav-B for the series to be valid 2

Adolescent Vaccination (Ages 11-19 years)

• Recombivax HB (ages 11-15): Either a 2-dose schedule at 0 and 4-6 months OR a 3-dose schedule at 0,1, and 6 months using 10 μg (0.5 mL) 1, 2
• Engerix-B (ages 11-19): 10 μg (0.5 mL) in a 3-dose schedule at 0,1, and 6 months 2

Special Population Schedules

Hemodialysis and Immunocompromised Adults (≥20 years)

• Recombivax HB: 40 μg (1.0 mL) in a 3-dose schedule at 0,1, and 6 months 2
• Engerix-B: 40 μg (2.0 mL) in a 4-dose schedule at 0,1,2, and 6 months 1, 2, 3
  • This 4-dose regimen achieves 67% seroprotection in hemodialysis patients, substantially lower than healthy adults 2

Pregnant Women

• Only use Engerix-B, Recombivax HB, or Twinrix in standard 3-dose schedules 1, 2
• Heplisav-B and PreHevbrio have insufficient pregnancy safety data and should not be used 1, 2

Accelerated Schedules

Standard Accelerated (4 doses)

• Administered at 0,1,2, and 12 months for rapid protection when needed 2
• The fourth dose at 12 months is essential for long-term immunity 2

Twinrix Super-Accelerated (4 doses)

• Administered at 0 days, 7 days, 21-30 days, and 12 months 1, 2
• The usual 4-day grace period does not apply to the first three doses of this schedule 1

Critical Management Principles

Interrupted Series

• Never restart the series if the vaccination schedule is interrupted 1, 2
• Simply continue where you left off and administer the next dose as soon as possible 1, 2
• For 3-dose series: second and third doses must be separated by ≥8 weeks 1
• Final dose must be administered ≥8 weeks after the second dose and ≥16 weeks after the first dose 1
• Minimum interval between first and second doses is 4 weeks 1

Dose Validity

• Vaccine doses administered ≤4 days before the minimum interval are considered valid 1, 2
• Switching vaccine brands within a series is permissible and does not require restarting 2

Common Pitfalls to Avoid

• Do not restart an interrupted series—this is the most common error; simply continue the schedule 1, 2
• Do not use Heplisav-B or PreHevbrio in pregnant women, hemodialysis patients, or children due to insufficient safety data 1, 2
• Do not assume all hepatitis B vaccines require 3 doses—Heplisav-B is a valid 2-dose option for adults ≥18 years 2
• Do not forget the fourth dose at 12 months when using accelerated schedules, as it is essential for long-term protection 2
• Do not delay vaccination for serologic testing—the first dose should be administered immediately after blood collection without awaiting results 1, 2