Hepatitis A Vaccine Dosing and Schedule
For routine immunization, all children should receive hepatitis A vaccine starting at 12-23 months of age as a 2-dose series, with the second dose administered 6-12 months after the first dose. 1, 2, 3
Routine Childhood Vaccination
Standard Schedule (Ages 12 months and older)
- First dose: Administer at 12-23 months of age
- Second dose: Give 6-12 months after the first dose (Havrix) or 6-18 months after the first dose (Vaqta) 2
- Catch-up vaccination: Recommended for all unvaccinated children and adolescents aged 2-18 years 3
Dosing by Age and Product
- Children 12 months to 18 years:
- Adults ≥19 years:
- Twinrix (combined hepatitis A/B): 1.0 mL per dose, given as 3-dose series at 0,1, and 6 months (adults only) 2
All doses should be administered intramuscularly 2.
Special Populations
Infants (6-11 months)
For international travel only: Administer 1 dose before departure 1
- This travel dose does NOT count toward the routine 2-dose series
- Must restart the complete 2-dose series beginning at 12 months of age 1
Infants <6 months
- Vaccine not indicated
- For travel protection: Use immune globulin (IG) 0.1-0.2 mL/kg 1
Post-Exposure Prophylaxis (PEP)
Administer as soon as possible within 14 days of exposure 1
By Age and Risk Category
Infants <12 months:
- IG only: 0.1 mL/kg (vaccine not approved) 1
Healthy persons aged 12 months to 40 years:
- Hepatitis A vaccine: 1 dose (no IG needed) 1
Healthy persons >40 years:
- Hepatitis A vaccine: 1 dose 1
- IG (0.1 mL/kg) may be added based on provider's risk assessment 1, 4
- The evidence shows slightly delayed seroconversion in older adults, though protective levels are achieved by 30 days 4
Immunocompromised or chronic liver disease (≥12 months):
- Both vaccine AND IG required: Administer simultaneously at different anatomic sites 1
- Vaccine: 1 dose
- IG: 0.1 mL/kg 1
Vaccine contraindicated (any age ≥12 months):
- IG only: 0.1 mL/kg 1
Important PEP Considerations
- The second dose is NOT required for PEP effectiveness 1
- However, complete the 2-dose series (second dose at ≥6 months) for long-term immunity 1
- Do not administer the second dose sooner than 6 months after the first, regardless of exposure 1
Pre-Exposure Prophylaxis for Travel
Administer vaccine as soon as travel is considered; do not delay 1
By Age Group
Infants 6-11 months:
Children and adults 12 months to 40 years:
- 1 dose of vaccine (no IG needed) 1
Adults >40 years:
Immunocompromised (all ages):
IG Dosing for Travel (when used)
- Travel up to 1 month: 0.1 mL/kg 1
- Travel up to 2 months: 0.2 mL/kg 1
- Travel ≥2 months: 0.2 mL/kg every 2 months 1
Critical Timing Considerations
Vaccine provides protection:
- Reliably by 4 weeks after first dose 2
- May provide protection as early as 2 weeks 2
- 88% seroconversion at 14 days post-vaccination 5
Important interaction: If IG is administered, delay MMR and varicella vaccines for at least 3 months, as IG can inhibit immune response to these live vaccines 1
Common Pitfalls to Avoid
Do not count the 6-11 month travel dose toward the routine series—this is a critical error that leaves children inadequately protected 1
Do not give the second dose earlier than 6 months after the first, even in post-exposure settings 1
For immunocompromised patients and those with chronic liver disease in PEP settings: Always give both vaccine AND IG simultaneously at different sites—vaccine alone is insufficient 1
When administering both vaccine and IG: Use separate anatomic sites (e.g., different limbs) 1
For adults >40 years in PEP: While vaccine alone is acceptable, consider adding IG based on individual risk assessment, as older adults may have slightly delayed immune response 4