Class: Vaccine
Dosage Forms. Intramuscular Suspension: Havrix, 720 ELISA units/0.5 mL, 1440 ELISA units/mL; Vaqta 25 units/0.5 mL, 50 units/1 mL; also available in combination with hepatitis B vaccine
Common FDA Label Indication, Dosing, and Titration.
1. Hepatitis A prophylaxis: Adults, Havrix 1440 ELISA units IM once, with a second dose 6-12 mo later, or Vaqta 50 units IM once, with a second dose 6-18 mo later; Children 12 mo to 18 y, Havrix 720 ELISA units IM once, with a second dose 6-12 mo later, or Vaqta 25 units IM once, with a booster dose 6-18 mo later
Off-Label Uses.
1. Hepatitis A postexposure prophylaxis for individuals aged 1-40 y: Same regimen as for preexposure prophylaxis; vaccine series should be started within 2 wk of exposure
Drug Characteristics: Hepatitis A Vaccine, Inactivated
Medication Safety Issues: Hepatitis A Vaccine, Inactivated
Drug Interactions: Hepatitis A Vaccine, Inactivated
Adverse Reactions: Hepatitis A Vaccine, Inactivated
Efficacy Monitoring Parameters. Prevention of hepatitis A infection; although antibody concentrations might be measured, routine measurement for vaccine response is not recommended.
Toxicity Monitoring Parameters. Liver function tests for adults at risk for liver failure.
Key Patient Counseling Points. Return to provider for booster dose in 6-12 mo, or 6-18 mo after first dose (depending on product initially used).
Clinical Pearls. Not indicated for children less than 12 mo of age. The vaccines are interchangeable, so second dose can be administered with the other brand of vaccine. Administer 2 wk prior to exposure (travel or international adoption of child). Vaccination recommended for all children 12 mo and older, and adults at risk for hepatitis A infection, including homosexual men, IV drug users, patients with chronic liver disease, international travelers, and those in close contact with those from endemic areas (Africa, India, etc). Hepatitis A transmits via oral/fecal route. After vaccination, 94-100% seroconversion within 1 mo.