From the Guidelines
The Hepatitis A vaccine should be administered as soon as possible, within 2 weeks of exposure, for postexposure prophylaxis in individuals aged ≥12 months, with a second dose recommended at least 6 months after the first dose for long-term immunity 1.
Key Considerations
- For individuals aged ≥12 months who have been exposed to HAV, a single dose of HepA vaccine should be administered as soon as possible, with the option of co-administering immune globulin (IG) for those aged >40 years or with certain risk factors 1.
- Infants aged <12 months and persons for whom the vaccine is contraindicated should receive IG (0.1 mL/kg) instead of HepA vaccine, as soon as possible and within 2 weeks of exposure 1.
- Immunocompromised persons or those with chronic liver disease should receive both IG (0.1 mL/kg) and HepA vaccine simultaneously in a different anatomic site as soon as possible after exposure 1.
Timing of Vaccination
- The first dose of HepA vaccine should be administered as soon as possible after exposure, with a second dose recommended at least 6 months after the first dose for long-term immunity 1.
- For preexposure protection, the vaccine can be administered at any time, with a second dose recommended at least 6 months after the first dose 1.
Special Considerations
- MMR and varicella vaccines should not be administered sooner than 3 months after IG administration 1.
- The provider's risk assessment should determine the need for IG administration in addition to HepA vaccine 1.
From the Research
Recommended Timing for Hepatitis A Vaccine
The recommended timing for the Hepatitis A (Hep A) vaccine varies depending on the age of the individual and the specific vaccine preparation.
- For adults, the recommended schedule is a 1.0-mL intramuscular dose initially, followed by a booster dose 6-12 months later 2.
- For children 2-17 years of age, the recommended schedule is 0.5 mL initially, followed by a booster dose 6-18 months later 2.
- Another vaccine preparation, Havrix, has a recommended adult dosage schedule of a 1.0-mL intramuscular dose initially, followed by a 1.0-mL booster dose 6-12 months later 2.
- Patients 2-18 years of age should receive doses of 0.5 mL (720 ELISA units) for Havrix 2.
Flexibility in Booster Timing
Studies have shown that the timing of the booster dose may not be critical for the antibody response 3.
- A 0-12 or 0-6 vaccination schedule can increase vaccination compliance 3.
- Preliminary data show that the persistence of HAV antibodies until month 12 allows for flexibility in the administration of the booster: month 6 or 12 3.
Last-Minute Travelers
For last-minute travelers, hepatitis A vaccine can be administered at any time before departure, as it will still provide travelers with protection 4.
- Seroconversion can occur within 2 weeks of vaccination, and some individuals may develop antibodies as early as 12 days after vaccination 4.
- The hepatitis A virus has an average incubation period of 28 days, making last-minute vaccination still effective in preventing the disease 4.
Postexposure Prophylaxis
Hepatitis A vaccine can be used as an alternative to immune globulin for postexposure prophylaxis, offering long-term protection 5.
- A study comparing hepatitis A vaccine and immune globulin for postexposure prophylaxis found that both provided good protection, although the vaccine may have slightly lower efficacy 5.