hepatitis A vaccine (Harvix, VAQTA)

Indications

• active immunization of persons >= 2 years of age against hepatitis A
  • persons (including military) traveling to or working in countries where hepatitis A is endemic (South Asia, Africa, South American, Central America, including Mexico)
    • >= 1 month prior to departure to endemic area*
    • NOT needed for travel to Canada, western Europe, Australia, New Zealand, Japan
  • sexually active homosexual & bisexual men
  • illicit drug users
  • persons with chronic liver disease
  • patients with clotting factor disorders
    • those that receive clotting factor concentrates
  • persons with occupational risk
    • laboratory workers who handle hepatitis A virus
  • routine vaccination of children prevents outbreaks & may confer herd immunity on the population
  • all toddlers age 12-23 months
  • homeless
  • incarceration
  • HIV1 infection
  • exposure to hepatitis A (within 2 weeks)

Limitations:

• may not prevent hepatitis A infection in patients who have unrecognized hepatitis A infection at the time of vaccination
• may not prevent infection in patients who do not achieve protective antibody titers
• the lowest protective titer has not been established

* should be given with immune globulin to persons travelling within 2 weeks; immune globulin alone no longer recommended

* hepatitis A immune globulin* not necessary before travel to endemic area or post-exposure in healthy person < 40 years

• administer single dose of hepatitis A vaccine with booster as scheduled

Contraindications

• hypersensitivity to any component of the vaccine

Caution:

• do not inject in gluteal region, response may be suboptimal
• shake vial or syringe well before use

pregnancy-category C

safety in lactation ?

Dosage

Primary immunization:*

• Harvix:
  • Children 2-18 years: 720 ELU (0.5 mL) IM in deltoid
  • Adults > 18 years: 1440 ELU (1 mL) IM in deltoid
• VAQTA:
  • Children 2-17 years: 25 units (0.5 mL)
  • Adults >= 18 years: 50 units (1 mL)

* 90% effective within 2-4 weeks

Booster:

• recommended at any time between 6-12 months after primary immunization

Injection:

• Harvix:
  • 720 ELU/0.5 mL (0.5 mL vial)
  • 1440 ELU/mL (1 mL vial, 1 mL syringe)
• VAQTA:
  • 25 units/0.5 mL (0.5 mL vial, 0.5 mL syringe)
  • 50 units/1 mL (1 mL vial, 1 mL syringe)
• combined hepatitis A & B vaccine: 0, 7 & 21-30 days
  • booster required at 12 months to ensure long-term protection

Pharmacokinetics

• protective antibodies develop in ~100% of health patients within 2-4 weeks
• elimination: liver

Adverse effects

• most common (1-10%)
  • headache, fatigue, fever (rare), transient abnormal LFTs, inflammation at injection site
• thrombocytopenic purpura in children age 7-17 years of age

Notes

• may be administered concomitantly with immune globulin, although titer is likely to be lower than if vaccine is given alone
• may be administered concomitantly with hepatitis B vaccine Twinrix is combined hepatitis A/ hepatitis B vaccine

More general terms

• vaccine

Additional terms

• hepatitis A infection
• hepatitis A virus (HAV)

Component of

• hepatitis a vaccine/hepatitis b vaccine (Twinrix)