What is the routine vaccination schedule for hepatitis A and hepatitis B (including the combined hepatitis A/B vaccine) in adults?

Routine Hepatitis A and B Vaccination Schedules for Adults

For hepatitis B alone, use a 2-dose series (Heplisav-B at 0 and 1 month) or a 3-dose series (Engerix-B or Recombivax HB at 0,1, and 6 months); for hepatitis A alone, use a 2-dose series at 0 and 6-12 months; when both vaccines are indicated, use Twinrix with either a standard 3-dose schedule (0,1,6 months) or an accelerated 4-dose schedule (0,7,21-30 days, and 12 months). 1, 2, 3

Hepatitis B Vaccination Schedules

Standard Options for Adults

• The CDC recommends either a 2-dose series (Heplisav-B) at 0 and 1 month with at least 4 weeks between doses, or a 3-dose series (Engerix-B or Recombivax HB) at 0,1, and 6 months. 1, 2, 4

• Alternative 3-dose schedules at 0,1,4 months or 0,2,4 months produce similar seroprotection rates to the standard 0,1,6-month schedule and may be used when ensuring follow-up is difficult. 2

• After the standard 3-dose series, more than 90% of adults under 40 years achieve protective antibody levels, though response rates decline with age. 2

Critical Timing Rules

• Minimum intervals must be strictly observed: 4 weeks between doses 1 and 2,8 weeks between doses 2 and 3, and 16 weeks between doses 1 and 3. 2, 4

• Doses given ≤4 days before the minimum interval are considered valid ("grace period"). 2

• If the series is interrupted, never restart—simply continue where you left off, as there is no maximum interval between doses. 2, 4

Special Populations

• Hemodialysis patients and immunocompromised adults require 40 μg doses (double the standard dose) of Recombivax HB at 0,1, and 6 months, with annual anti-HBs testing and booster doses when levels fall below 10 mIU/mL. 2

• Pregnant women should only receive Engerix-B, Recombivax HB, or Twinrix—do not use Heplisav-B or PreHevbrio due to insufficient safety data in pregnancy. 2, 4

Hepatitis A Vaccination Schedule

Standard Regimen

• Administer a 2-dose series of single-antigen hepatitis A vaccine at 0 and 6-12 months (Havrix) or 0 and 6-18 months (Vaqta). 1

• The first dose should be given as soon as protection is needed, ideally at least 2 weeks before anticipated exposure (e.g., international travel). 1

Indications for Hepatitis A Vaccination

• Men who have sex with men, persons who use injection or non-injection illicit drugs, persons with chronic liver disease, persons traveling to endemic regions, and anyone seeking protection from hepatitis A. 1

Combined Hepatitis A/B Vaccine (Twinrix)

When to Use Twinrix

• Reserve Twinrix for patients who need protection against both hepatitis A and B viruses—do not use it solely for hepatitis B vaccination when hepatitis A protection is not indicated. 2

• Appropriate populations include international travelers to endemic regions, men who have sex with men at risk for both infections, and persons with chronic liver disease requiring both vaccines. 2

Standard Twinrix Schedule

• Administer 3 doses at 0,1, and 6 months for routine immunization. 1, 2, 3

• Each 1 mL dose contains 720 EL.U. of hepatitis A antigen and 20 μg of hepatitis B surface antigen. 3

Accelerated Twinrix Schedule

• For rapid protection (e.g., last-minute travelers), use 4 doses administered on days 0,7, and 21-30, followed by a mandatory booster at 12 months. 1, 2, 3, 5, 6

• The accelerated schedule provides 63.2% anti-hepatitis B seroprotection by day 37 (versus 43.5% with monovalent hepatitis B vaccine) and 98.5% anti-hepatitis A seroconversion by day 37. 6

• The 12-month booster dose is essential for long-term immunity and must not be omitted. 2, 3

• After the first two doses (months 0 and 1) of the standard schedule, most adults achieve substantial immunity allowing travel without waiting for the third dose. 3

Common Pitfalls to Avoid

• Never restart a hepatitis B series if interrupted—this wastes doses and delays protection; simply continue where you left off. 2, 4

• Do not give the third hepatitis B dose before 16 weeks from the first dose, even if 8 weeks have passed since the second dose. 2

• Do not use standard adult hepatitis B doses in hemodialysis patients—they require 40 μg doses. 2

• Do not omit the 12-month booster when using the Twinrix accelerated schedule, as it is required for long-term protection. 2, 3

• Do not use Twinrix simply for hepatitis B vaccination when the patient has no indication for hepatitis A protection, as this exposes them to unnecessary antigen. 2

• For infants, the final hepatitis B dose must not be administered before 24 weeks of age, regardless of when earlier doses were given. 2, 4