Vaccines: Hepatitis A

Specific vaccination recommendations vary among countries or even within a given country. Local or country-specific guidelines should be consulted.

1. Vaccines include hepatitis A vaccine, a combined hepatitis A and hepatitis B vaccine, and a combined typhoid and hepatitis A vaccine. The vaccines contain inactivated hepatitis A viruses.

2. Indications: In adults vaccination is recommended in people at increased risk of infection (according to the Canadian Immunization Guide from the Public Health Agency of Canada):

1) Travelers to hepatitis A endemic countries.

2) Individuals with chronic liver disease.

3) Men who have sex with men (MSM).

4) Injectable and noninjectable illicit drug users.

5) Individuals living in communities at risk of hepatitis A outbreaks or in which hepatitis A is endemic.

6) Household or close contacts of children adopted from hepatitis A endemic countries.

7) Military personnel and humanitarian relief workers.

8) People receiving repeated replacement of plasma-derived clotting factors.

9) Workers involved in research on hepatitis A virus or production of hepatitis A vaccine who may be exposed to hepatitis A virus.

10) Zookeepers, veterinarians, and researchers who handle nonhuman primates.

3. Contraindications include general contraindications for all inactivated vaccines, including anaphylaxis after a previous vaccine dose. Vaccination should be postponed in patients with moderate to severe acute illness. Pregnancy and breastfeeding are not contraindications to vaccination.

4. Immunization schedule: A primary vaccination series with hepatitis A vaccine includes 2 doses administered IM in the deltoid muscle (in adults) at month 0 and at 6 to 36 months, depending on the brand of vaccine used. In exceptional cases of patients with significant thrombocytopenia or coagulopathy, the vaccine can be administered subcutaneously, but this is associated with weaker immune responses. Vaccination with combined hepatitis A/B vaccine requires 3 doses over a 6-month period. Vaccination for travelers can be performed up to the day of departure. Booster doses following routine immunization are not routinely required for hepatitis A.

The use of intramuscular immunoglobulin (IMIG) may be considered for protection in patients with contraindications to vaccination. IMIG is dosed at 0.02 mL/kg for up to 3 months of protection or 0.06 mL/kg for up to 6 months of protection.

Serologic testing to detect immunity to hepatitis A is not recommended because of its poor sensitivity.

5. Postexposure prophylaxis with a single dose of hepatitis A vaccine after contact of an unvaccinated individual with a person with hepatitis A (household contacts, contacts of children in kindergarten or a child care setting, and contacts or clients of food handlers) is recommended. Ideally, vaccination should occur within 14 days of exposure but may still be considered later. Adults aged ≥60 years, those with chronic liver disease, and the immunocompromised should receive both immunoglobulin and a single dose of hepatitis A vaccine.