Engerix-B

Product Overview

• Brand Name: Engerix-B
• Type: Hepatitis B vaccine (recombinant)
• Form: Suspension for injection
• Dosage Forms:
• Pediatric/Adolescent Dose: 0.5 mL containing 10 mcg of hepatitis B surface antigen (HBsAg) adsorbed onto 0.25 mg of aluminium hydroxide.
• Adult Dose: 1.0 mL containing 20 mcg of HBsAg adsorbed onto 0.5 mg of aluminium hydroxide.
• Manufacturer: GlaxoSmithKline Inc.

Indications

• Purpose: Active immunization against hepatitis B virus (HBV) infection.
• Usage: For individuals from birth onwards, for primary immunization or as a booster dose.
• Expected Protection: Can prevent hepatitis D, which occurs only in the presence of hepatitis B infection.

Contraindications

• Known hypersensitivity to any component of the vaccine or previous doses of Engerix-B.
• Should not be administered to individuals with severe febrile infections.

Dosage and Administration

• Administration Route: Intramuscular injection.
• Adults: Inject in the deltoid region.
• Neonates and infants: Preferably in the anterolateral thigh.
• For patients with severe bleeding tendencies, subcutaneous administration is recommended.
• Standard Schedule:
• 0, 1, and 6 months for optimal protection.
• Accelerated Schedule:
• 0, 1, 2 months with a booster at 12 months for quicker protection.
• Rapid Schedule:
• 0, 7, and 21 days with a booster at 12 months for very rapid protection.
• Alternative Schedule:
• 11-15 years: 2 doses at 0 and 6 months for adolescents.
• Special Populations:
• Renal Insufficiency (≥16 years): 4 double doses (2 x 20 mcg) at 0, 1, 2, and 6 months.
• Immunocompromised Patients: 2 x 1.0 mL doses (40 mcg total) per administration.
• Pediatric Renal Insufficiency: Additional doses may be required to ensure adequate anti-HBs levels.

Warnings and Precautions

• Anaphylactic Reactions: Appropriate medical treatment should be available for rare anaphylactic reactions.
• Administration Site: Should not be administered intradermally or intravenously.
• Chronic Liver Disease Patients: Vaccination is recommended as HBV infection can be severe in these patients.
• Immune Response Factors: Factors like older age, male gender, obesity, smoking, and route of administration may affect the immune response.
• Pregnancy and Lactation:
• Pregnant Women: Adequate studies not available; vaccination may be considered in high-risk situations.
• Breast-feeding: Unknown if excreted in human milk; caution is advised.

Adverse Reactions

• Very Common (>10%): Irritability, pain, and redness at injection site, tiredness.
• Common (1-10%): Appetite loss, headache, drowsiness, gastrointestinal symptoms (nausea, vomiting, diarrhea, abdominal pain), injection site swelling, malaise, fever.
• Uncommon (0.1-1%): Dizziness, myalgia, flu-like symptoms.
• Rare (<0.1%): Lymphadenopathy, paraesthesia, rash, pruritus, urticaria, arthralgia.
• Post-Market Adverse Reactions:
• Infections: Meningitis.
• Blood Disorders: Thrombocytopenia.
• Immune Disorders: Anaphylaxis, allergic reactions, serum sickness-like symptoms.
• Neurological Disorders: Encephalopathy, neuritis, neuropathy, paralysis, convulsions, Guillain-Barré syndrome, multiple sclerosis.
• Skin Disorders: Angioneurotic edema, lichen planus, erythema multiforme.
• Respiratory Disorders: Bronchospasm.

Clinical Trials and Efficacy

• Clinical Trial Overview:
• Studies conducted on healthy adults, infants, and special populations.
• Various dosing schedules evaluated, including standard, accelerated, rapid, and alternative schedules.
• Efficacy Results:
• Standard Schedule: >96% seroprotection rate at month 7.
• Accelerated Schedule: 95.8% seroprotection at month 13.
• Rapid Schedule: 98.6% seroprotection at month 13.
• Alternative Schedule (Adolescents): 96.7% seroprotection at month 7.
• Special Populations:
• Children: Similar immunogenicity to adults.
• Neonates: Effective response similar to adults and children.
• Older Adults: Slightly lower antibody titers but effective protection.
• Chronic Hepatitis C Patients: Similar response to healthy subjects.
• Hemodialysis Patients: Lower antibody response; booster doses often required.
• Type 2 Diabetes Mellitus Patients: Lower seroprotection rates in older age groups.

Storage and Handling

• Storage Temperature: 2-8°C (refrigeration).
• Protection from Light: Store in original package to protect from light.
• Do Not Freeze: Freezing destroys the vaccine.