Hepatitis B immune globulin

Hepatitis B Immune Globulin (HBIG) is a medication made from human plasma containing antibodies to Hepatitis B (HBV). It is used to prevent HBV infection in individuals who are at high risk of contracting the virus, including those who have been exposed to HBV through sexual contact, needlestick injuries, or have been born to HBV-infected mothers. HBIG provides passive immunity by supplying the body with antibodies against the virus, offering immediate but temporary protection.

Indications

HBIG is indicated for post-exposure prophylaxis of Hepatitis B infection. The specific situations include:

• Immediate protection for newborns born to hepatitis B surface antigen (HBsAg) positive mothers.
• Post-exposure prophylaxis for individuals accidentally exposed to HBV-contaminated blood or body fluids. This includes healthcare workers exposed via needlestick injury and individuals exposed through sexual contact with an HBV-infected person.
• Protection for individuals undergoing liver transplantation when the liver donor is HBsAg positive.

Administration

HBIG is administered intramuscularly. The dosage and the number of doses depend on the indication for use. For newborns of HBsAg-positive mothers, the first dose is usually given within 12 hours of birth, alongside the first dose of the Hepatitis B vaccine. For post-exposure prophylaxis in adults, the timing and number of doses depend on the nature of the exposure and the individual's vaccination history.

Mechanism of Action

HBIG works by providing passive immunity to HBV. The antibodies in HBIG bind to the hepatitis B virus and neutralize it, preventing it from infecting cells in the liver. This action is temporary, as the antibodies are eventually cleared from the body, hence the importance of concurrent or follow-up vaccination for long-term protection.

Efficacy

When administered correctly, HBIG is highly effective in preventing HBV infection if given shortly after exposure. For newborns of HBsAg-positive mothers, the combination of HBIG and the hepatitis B vaccine series has shown to be more than 95% effective in preventing transmission.

Side Effects

Common side effects of HBIG include soreness at the injection site, headache, and mild fever. Severe allergic reactions are rare but can occur, especially in individuals who are allergic to human immune globulins.

Precautions

Before receiving HBIG, individuals should inform their healthcare provider if they have had any prior reactions to human immune globulins or have immunoglobulin A (IgA) deficiency.

Conclusion

Hepatitis B Immune Globulin is a crucial component in the prevention of HBV infection in individuals at high risk of exposure. Its use, in combination with the hepatitis B vaccine, provides effective short-term and long-term protection against HBV.