What are the recommendations for the Hepatitis A vaccine, including administration schedule and special considerations for individuals with liver disease or weakened immune systems?

Hepatitis A Vaccine Recommendations

All children in the United States should receive hepatitis A vaccine starting at 12-23 months of age as a 2-dose series, and persons with chronic liver disease or immunocompromising conditions should be vaccinated without delay, as the inactivated vaccine is both safe and effective in these populations. 1

Administration Schedule

Standard Dosing Regimens

• Havrix: Administer at 0 and 6-12 months for the 2-dose series 1
• Vaqta: Administer at 0 and 6-18 months for the 2-dose series 1
• Twinrix (combined hepatitis A and B): Administer 3 doses at 0,1, and 6 months 1

The vaccines are interchangeable—if the series is started with one brand, it can be completed with another, though using the same vaccine is preferable. 1

Key Scheduling Principles

• If the immunization schedule is interrupted, simply continue where you left off rather than restarting the entire series. 1
• The second dose should not be administered sooner than 6 months after the first dose, regardless of exposure risk 1
• For postexposure prophylaxis, only one dose is required for immediate protection, though the series should be completed for long-term immunity 1

Special Populations

Persons with Chronic Liver Disease

Individuals with chronic liver disease (including cirrhosis from any cause) must be vaccinated, as they face substantially higher risk of severe complications and mortality from hepatitis A infection. 1

• Vaccination should be administered as soon as the diagnosis of chronic liver disease is established 1
• The standard 2-dose series provides adequate protection in this population 2
• No special dosing adjustments are required 2

Immunocompromised Individuals

Immunocompromising conditions are NOT a contraindication to hepatitis A vaccine—the vaccine is an inactivated preparation and has not been shown to cause increased safety risks in persons with primary or secondary immunodeficiencies. 1

• HIV-infected persons should be vaccinated as close to diagnosis as possible 1
• For postexposure prophylaxis in immunocompromised persons aged ≥12 months, administer both vaccine AND immune globulin (0.1 mL/kg) simultaneously at different anatomic sites 1
• For preexposure protection in immunocompromised travelers of all ages, consider adding immune globulin (0.1-0.2 mL/kg) based on provider risk assessment 1

HIV-Infected Patients

• Vaccination should occur as early as possible after HIV diagnosis to maximize immune response 1
• Serologic testing 1-2 months after the second vaccine dose is recommended to assess immunogenicity 1
• A repeat vaccine series should be administered to those who remain seronegative 1

High-Risk Groups Requiring Vaccination

Medical Indications

• Chronic liver disease of any etiology (including hepatitis B, hepatitis C, cirrhosis, alcoholic liver disease) 1
• Persons receiving clotting factor concentrates 1
• End-stage renal disease and hemodialysis patients 1

Behavioral Indications

• Men who have sex with men (MSM) 1
• Users of injection or noninjection illicit drugs 1
• Persons experiencing homelessness (all persons aged ≥1 year) 3

Preimmunization serologic testing is NOT recommended for adolescents and young adults in these risk groups—just vaccinate them. 1

Travel-Related Indications

• All persons traveling to or working in countries with high or intermediate hepatitis A endemicity should be vaccinated before departure. 1
• Protection is reliably present by 4 weeks after the first dose and may provide protection as early as 2 weeks 1
• For travelers departing in less than 4 weeks, still administer the vaccine; for those over age 40, consider adding immune globulin (0.1-0.2 mL/kg) at a different injection site based on risk assessment 1

Occupational Indications

• Persons working with hepatitis A virus-infected primates or with HAV in research laboratory settings 1

Universal Childhood Vaccination

• All children should receive the first dose at 12-23 months of age 1
• Catch-up vaccination should be considered for unimmunized children aged 2-18 years, particularly in areas with increasing incidence or ongoing outbreaks 1

Postexposure Prophylaxis

Age-Based Recommendations

• Ages 12 months to 40 years (healthy): Administer 1 dose of vaccine only 1
• Age >40 years (healthy): Administer 1 dose of vaccine; provider may also add immune globulin (0.1 mL/kg) based on risk assessment 1
• Age ≥12 months with immunocompromise or chronic liver disease: Administer both vaccine AND immune globulin (0.1 mL/kg) simultaneously at different anatomic sites 1
• Age <12 months: Administer immune globulin (0.1 mL/kg) only 1

Postexposure prophylaxis must be administered within 2 weeks of exposure to be effective. 1

Contraindications and Precautions

Absolute Contraindications

• Life-threatening allergic reaction to a previous dose of hepatitis A vaccine 1
• Allergy to any vaccine component (aluminum hydroxide, phenoxyethanol) 1

Storage Requirements

• Store and ship between 2-8°C (36-46°F) 1
• Do NOT freeze the vaccine—freezing destroys vaccine potency 1
• Brief storage at up to 37°C (98°F) for up to 1 week does not affect immunogenicity or reactogenicity 1

Common Pitfalls to Avoid

• Do not withhold vaccination from immunocompromised patients—this is a common error, as the inactivated vaccine is safe in this population 1
• Do not restart the series if interrupted; simply continue where you left off 1
• Do not perform routine preimmunization serologic testing in adolescents and young adults—it delays vaccination and is not cost-effective 1
• Do not assume that persons with chronic liver disease need special dosing—the standard schedule is appropriate 2
• For travelers over age 40 departing soon, do not rely on vaccine alone for postexposure prophylaxis—consider adding immune globulin based on risk assessment 1