Immune globulin (IG, GamaSTAN, Grifols Therapeutics) is a sterile preparation of concentrated antibodies (i.e., immunoglobulins) made from pooled human plasma processed by cold ethanol fractionation. GamaSTAN is the only IG product licensed in the United States for the prevention of hepatitis A virus (HAV) infection. Only plasma that has tested negative for hepatitis B surface antigen, antibody to human immunodeficiency virus (HIV), and antibody to hepatitis C virus (HCV) is used to produce IG. In addition, the Food and Drug Administration requires that the process used to produce IG include a viral inactivation step or that final products test negative for HCV-RNA by polymerase chain reaction. Anti-HAV concentrations differ among IG lots and decreasing concentrations have been observed over the past 30 years, probably because of the decreasing prevalence of previous HAV infection among plasma donors. In 2017, the dosing of GamaSTAN for HAV prevention was increased to reflect this change in anti-HAV potency.
Ask the Experts: Hepatitis A: Immune Globulin
IG provides protection against HAV infection through passive transfer of antibody. Depending on the IG dosage, protection lasts from 1 to 2 months.
When administered for preexposure prophylaxis, a dose of 0.1 mL/kg will provide protection for up to 1 month and a dose of 0.2 mL/kg will provide protection for up to 2 months. If longer term protection is required and vaccination is contraindicated, a dose of 0.2 mL/kg can be repeated every 2 months. There is no maximum number of times the bimonthly doses of IG may be repeated as long as hepatitis A prophylaxis is required.
For postexposure prophylaxis, the recommended dosage is 0.1 mL/kg.
Intramuscular IG is available in single-use vials (2 mL and 10 mL). It should be administered intramuscularly, preferably in the anterolateral aspects of the upper thigh and the deltoid muscle of the upper arm. Do not use the gluteal region as an injection site because of the risk of injury to the sciatic nerve.
Serious adverse events from GamaSTAN IG are rare. Anaphylaxis has been reported after repeated administration to people with known immunoglobulin A (IgA) deficiency; thus, IG should not be administered to these people. IG products including GamaSTAN have been associated with the formation of blood clots (thrombosis) after administration, particularly if the patient has other risk factors for thrombosis. Patients should be counseled about this risk.
Yes. Pregnancy or lactation is not a contraindication to IG administration if clearly needed.
Yes. IG may be given any time before or after inactivated vaccines like HepA. However, the antibodies in IG may interfere with the effectiveness of certain live-virus vaccines, such as measles, mumps, and rubella (MMR) and varicella vaccines. CDC recommends waiting at least 6 months from the date of IG administration before administering MMR and varicella vaccines.
Please see details of the recommendations for the use of IG for the prevention of hepatitis A provided in Table 4 (page 19) and Appendices A and B of the 2020 ACIP recommendations for the prevention of hepatitis A infection: www.cdc.gov/mmwr/volumes/69/rr/pdfs/rr6905a1-H.pdf.
Below is a brief summary of the recommendations:
Preexposure prophylaxis with IG for travel to areas of intermediate or high hepatitis A endemicity:
- Infants younger than age 6 months and other travelers for whom HepA vaccine is declined or contraindicated
- Previously unvaccinated people with chronic liver disease vaccinated within 2 weeks of departure may consider IG in addition to vaccination, based upon the clinician’s risk assessment
- Previously unvaccinated people who are immunocompromised may consider IG in addition to vaccination, regardless of the timing of vaccination, based upon the clinician’s risk assessment
- Previously unvaccinated people who are over age 40 years and vaccinated within 2 weeks of departure may consider IG in addition to vaccination, based upon the clinician’s risk assessment
Postexposure prophylaxis with IG within 2 weeks after exposure to hepatitis A virus (HAV):
- Infants under age 12 months
- Previously unvaccinated immunocompromised adults (including HIV+), in addition to vaccination
- Previously unvaccinated adults with chronic liver disease, in addition to vaccination
- Previously unvaccinated adults over age 40 years, consider IG in addition to vaccination, based upon clinician risk assessment
- People with HIV infection, previously vaccinated, consider IG following a high-risk exposure (household or sexual contact), based upon clinician risk assessment