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Hepatitis A&B

Hepatitis A+B vaccine contains paediatric dose of Hepatitis A and adult dose of Hepatitis B.

Minimum Intervals for the 3‑Dose Twinrix Series

The standard Twinrix (HepA‑HepB) series consists of three intramuscular doses at 0, 1, and 6 months. Minimum intervals:

• Between Dose 1 and Dose 2: at least 4 weeks (28 days)
• Between Dose 2 and Dose 3: at least 5 months (~20 weeks)

These intervals ensure optimal immune response to both hepatitis A and B.

Accelerated (Alternative) Twinrix Schedule for Rapid Protection

For rapid protection (e.g., imminent travel), an accelerated 4‑dose schedule may be used:
First dose: Day 0
Second dose: Day 7
Third dose: Day 21–30
Fourth (booster) dose: ≥12 months after the first dose
This regimen provides earlier protection when the routine schedule cannot be completed before exposure.

Completing the Series with Single‑Antigen Vaccines

If Twinrix is started but completion with single‑antigen vaccines is needed:
If 1 dose of Twinrix was given:
Complete with 2 adult doses of Hepatitis A (HepA)
Complete with 2 adult doses of Hepatitis B (HepB)
If 2 doses of Twinrix were given:
Complete with 1 adult dose of HepA
Complete with 1 adult dose of HepB

Key principles:

• Each Twinrix dose contains an adult dose of HepB and a paediatric dose of HepA.
• A Twinrix dose can substitute for any dose in the HepB series, but not for a full adult dose in the HepA series.
• Any combination of 3 doses of adult HepB or 3 doses of Twinrix constitutes a complete HepB series.
• 1 Twinrix dose + 2 adult HepA doses = complete HepA series.
• 2 Twinrix doses + 1 adult HepA dose = complete HepA series.

Reference: Immunize.org – HepA‑HepB (Twinrix) guidance

Twinrix – Product Information