There are times when a person needs protection against hepatitis A, but hepatitis A vaccine is either not recommended (e.g., in a person younger than 1 year of age) or the vaccine is contraindicated. In these situations, immune globulin (IG) is indicated. IG is a concentrated solution of antibodies that provides passive immunity against hepatitis A virus. IG also can be given to persons who have been exposed to hepatitis A virus as postexposure prophylaxis against hepatitis A.
IG provides passive immunity, which is not long lasting. Only infection with hepatitis A provides lifelong immunity, and vaccination with hepatitis A vaccine provides long-term active immunity.
Immune globulin (IG) is typically used for postexposure prophylaxis of hepatitis A in susceptible persons. Hepatitis A vaccine may be used for postexposure prophylaxis in healthy persons 12 months through 40 years of age. Immune globulin is preferred for persons older than 40 years of age. Immune globulin should be used for children younger than 12 months of age, immunocompromised persons, persons diagnosed with chronic liver disease, and persons for whom vaccine is contraindicated. Persons administered IG for whom hepatitis A vaccine also is recommended for other reasons should receive a dose of vaccine simultaneously with IG. Be sure the vaccine and the IG are administered in separate syringes and in separate anatomic sites.