Hepatitis B immunoglobulin

Hepatitis B Immunoglobulin (HBIG) is a blood product administered as part of the treatment and prevention of Hepatitis B virus (HBV) infection. HBIG is derived from the plasma of donors with high levels of antibodies to the hepatitis B virus. It provides passive immunity to individuals exposed to the virus, either through contact with infected blood, from mother to child at birth, or through other routes of transmission.

Indications

HBIG is indicated for the prevention of HBV infection in:

• Newborns of mothers who are positive for hepatitis B surface antigen (HBsAg).
• Individuals who have been exposed to HBV through needlestick injury, sexual contact, or mucosal exposure to infected blood.
• Patients undergoing liver transplantation when the liver donor is HBsAg-positive.

Mechanism of Action

HBIG works by providing passive immunity. It contains high levels of antibodies against the hepatitis B surface antigen (HBsAg), which neutralize the virus and help prevent it from infecting cells in the liver. This action is temporary, as the immunoglobulin is eventually metabolized by the body, hence the need for active vaccination to ensure long-term protection.

Administration

HBIG is administered intramuscularly. The dosage and schedule depend on the indication for use. For example, newborns of HBsAg-positive mothers receive a dose at birth, typically in conjunction with the first dose of the Hepatitis B vaccine to initiate active immunity.

Efficacy

When administered promptly after exposure to HBV, HBIG is highly effective in preventing infection. It is most effective when given within 24 hours of exposure, but it can still provide benefits when administered within 14 days.

Side Effects

Side effects of HBIG are generally mild and may include pain at the injection site, headache, and mild fever. Severe allergic reactions are rare but can occur, especially in individuals who have a history of severe allergic reactions to blood products.

Considerations

While HBIG is effective in providing immediate, short-term protection against HBV, it is not a substitute for the hepatitis B vaccine, which offers long-term protection. In most cases, HBIG is used in conjunction with the vaccine to provide both immediate and long-term immunity against HBV.

Conclusion

Hepatitis B Immunoglobulin is a critical component in the prevention of HBV infection in individuals at high risk of exposure. Its use, in combination with the hepatitis B vaccine, has significantly reduced the incidence of hepatitis B infection, particularly in newborns of infected mothers and healthcare workers exposed to the virus.