Question
Hepatitis B vaccine
Answer
Hepatitis B vaccine is a recombinant, subunit vaccine containing purified Hepatitis B surface antigen (HBsAg), produced by recombinant DNA technology (expressed in yeast).
Schedule: a birth dose (within 24 hours, important for preventing perinatal transmission) followed by additional doses as part of the primary series (e.g., at 6, 10, and 14 weeks).
Mechanism: stimulates active production of anti-HBs antibody; a subunit (non-live) vaccine, so it carries no risk of causing HBV infection.
High-risk group vaccination: recommended for healthcare workers, dialysis patients, household contacts of HBsAg-positive individuals.
Post-exposure prophylaxis: Hepatitis B Immunoglobulin (HBIG) plus vaccination for neonates born to HBsAg-positive mothers and high-risk needle-stick exposures.
Public health significance: universal infant vaccination has dramatically reduced chronic HBV infection, hepatocellular carcinoma, and cirrhosis incidence.

