Hepatitis B Immunoglobulin Vaccine

Hepatitis B immunoglobulin (HBIG), also called hepatitis B immune globulin, is a human plasma-derived immunoglobulin containing high concentrations of antibodies against hepatitis B surface antigen (anti-HBs). It belongs to the class of immune sera and immunoglobulins and provides passive immunization, meaning it supplies ready-made antibodies rather than stimulating the person's immune system to produce its own long-term response. HBIG binds to hepatitis B virus and helps prevent establishment of infection after a significant exposure. It is administered by injection, generally intramuscularly for post-exposure prophylaxis products; some products used for prevention of hepatitis B reinfection after liver transplantation have different administration requirements. HBIG is clinically important because protection from a hepatitis B vaccine does not develop immediately after vaccination, while HBIG can provide immediate, temporary antibody-mediated protection. Its protection is generally temporary, and HBIG is commonly used together with hepatitis B vaccination when indicated rather than as a substitute for vaccination. HBIG is not a hepatitis B vaccine and does not provide the same type of long-term active immunity.

Hepatitis B immune globulin was developed as a plasma-derived source of concentrated anti-HBs antibodies for prevention of hepatitis B following exposure. In the United States, the FDA recorded an original approval date of September 23, 1977 for a hepatitis B immune globulin product. Current FDA-labeled products are indicated for post-exposure prophylaxis after exposure to HBsAg-positive blood or materials, perinatal exposure in infants born to HBsAg-positive mothers, sexual exposure to an HBsAg-positive person, and certain household exposures involving infants. In the European Union, the EMA-authorised product Zutectra, containing human hepatitis B immunoglobulin, received European Commission marketing authorisation on November 30, 2009 for prevention of HBV reinfection in appropriate adults after liver transplantation for hepatitis B-related liver failure. Clinical use has subsequently been incorporated into established post-exposure and transplant prophylaxis programs.

HBIG is primarily used for post-exposure prophylaxis when a person has been exposed to hepatitis B virus and requires immediate passive antibody protection. Important situations include exposure to HBsAg-positive blood through needlestick or other percutaneous injury, mucosal exposure, sexual exposure, and prevention of infection in infants born to mothers who are HBsAg-positive. For people who are unvaccinated or incompletely vaccinated and have a significant exposure to an HBsAg-positive source, HBIG is generally given together with hepatitis B vaccine, at separate anatomical sites. HBIG may also be used for people who have failed to respond adequately to hepatitis B vaccination. Certain human hepatitis B immunoglobulin products have a separate indication for preventing HBV reinfection in selected adults after liver transplantation and are used with appropriate antiviral therapy. HBIG is not used to treat established chronic hepatitis B infection.

HBIG is administered according to the specific product, exposure type, patient age or weight, and clinical indication. For commonly used U.S. post-exposure prophylaxis, the CDC describes a dose of 0.06 mL/kg, administered intramuscularly, when HBIG is indicated. For an unvaccinated person exposed to an HBsAg-positive source, HBIG and hepatitis B vaccine should generally be administered as soon as possible, preferably within 24 hours, with the vaccine given at a separate anatomical site. Timing is particularly important after exposure; effectiveness decreases with delay, with practical limits depending on the exposure route. Infants born to HBsAg-positive mothers require prompt prophylaxis according to neonatal hepatitis B protocols. Treatment duration is indication-specific: HBIG may be a single post-exposure dose, repeated in selected vaccine nonresponders, or administered at scheduled intervals for transplant-related prophylaxis. Monitoring should be based on the underlying exposure and, when indicated, follow-up hepatitis B serology and vaccination response.

Common reactions to hepatitis B immunoglobulin are generally mild and may include pain, tenderness, redness, swelling or discomfort at the injection site. Some patients may experience headache, fatigue, fever, chills, nausea, vomiting, rash or other transient systemic symptoms. The frequency and severity of reactions vary according to the product and individual patient. Most injection-site reactions are temporary and can be managed with routine clinical observation and symptomatic care when appropriate. Patients should inform healthcare professionals about previous reactions to human immunoglobulin products before receiving treatment.

Serious reactions to HBIG are uncommon but can include severe hypersensitivity or anaphylaxis, particularly in people with a history of serious reactions to human immunoglobulins. Immunoglobulin products can rarely be associated with thrombotic events, hemolysis, aseptic meningitis, acute kidney injury or other systemic complications, although the risk depends on the product and patient characteristics. HBIG should not be administered intravenously when the product is intended for intramuscular use, and administration must follow the relevant product information. Because HBIG is derived from human plasma, manufacturing processes and donor screening are used to reduce the risk of transmission of infectious agents, but that risk cannot be considered absolutely zero. Treatment should be interrupted or discontinued if a clinically significant hypersensitivity reaction occurs.

Before administration, clinicians should assess the exposure circumstances, source HBsAg status where available, hepatitis B vaccination history, previous anti-HBs results where available, and any history of serious reactions to immunoglobulin products. HBIG is particularly important when rapid passive protection is required, but it should not replace completion of an indicated hepatitis B vaccination series. When HBIG and hepatitis B vaccine are given at the same visit, they should be administered at separate anatomical sites. Immunoglobulin administration can interfere with the immune response to certain live attenuated vaccines, so vaccination timing should be considered according to the specific immunoglobulin product and vaccine. Classic metabolic drug interactions are generally not a major issue because HBIG is an antibody preparation rather than a conventionally metabolised small-molecule drug. Special consideration may be required in patients with immunoglobulin hypersensitivity, IgA deficiency with anti-IgA antibodies, thrombotic risk, renal impairment or other conditions identified in the relevant product information.

Confirm the exposure type, source HBsAg status where available, vaccination history and previous documented anti-HBs response before selecting post-exposure prophylaxis. When HBIG is indicated, administration should occur as soon as possible, ideally within 24 hours for many exposure scenarios. Ensure HBIG and hepatitis B vaccine are injected at separate anatomical sites when both are required, and document the vaccine series and follow-up serology where indicated. For neonates exposed perinatally, prophylaxis should be coordinated promptly with obstetric and pediatric teams. Pharmacists and clinicians should verify the exact commercial product because concentration, route, presentation and dosing instructions can differ between preparations. For liver-transplant recipients receiving HBIG to prevent HBV reinfection, coordination with transplant specialists and appropriate antiviral therapy is essential, with monitoring of HBsAg, HBV DNA and other relevant markers according to the transplant protocol.