Ask the Experts: Hepatitis A: Twinrix

Results (3)

Twinrix is licensed as a 3-dose series for people age 18 years and older. If Twinrix is not available or if you choose not to use Twinrix to complete the hepatitis A (HepA) and hepatitis B (HepB) series, you should do the following:

  • If 1 dose of Twinrix was given, complete the series with 2 adult doses of HepA and 2 adult doses of HepB.
  • If 2 doses of Twinrix were given, complete the schedule with 1 adult dose of HepA and 1 adult dose of HepB.

Another way to consider this is as follows:

  • A dose of Twinrix contains a standard adult dose of HepB and a pediatric dose of HepA. So, a dose of Twinrix can be substituted for any dose of the HepB series but not for any dose of the HepA series.
  • Any combination of 3 doses of adult HepB or 3 doses of Twinrix is a complete series of HepB vaccine
  • One dose of Twinrix and 2 doses of adult HepA is a complete series of HepA
  • Two doses of Twinrix and 1 dose of adult HepA is a complete series of HepA
Last reviewed: July 21, 2023

Twinrix (GSK) is an inactivated combination vaccine containing both hepatitis A virus (HAV) and hepatitis B virus (HBV) antigens. The vaccine contains 720 EL.U. of hepatitis A antigen (half of the Havrix adult dose) and 20 mcg of hepatitis B antigen (the full Engerix-B adult dose).

In the U.S., Twinrix is licensed for use in people who are age 18 years or older. It can be administered to people who are at risk for both hepatitis A and hepatitis B, such as certain international travelers, people with HIV infection, people with chronic liver disease not caused by hepatitis B, men who have sex with men, people who use drugs, or to people who simply want to be immune to both diseases. Primary immunization consists of 3 doses given intramuscularly on a 0-, 1-, and 6-month schedule. In 2007, the FDA also approved a 4-dose schedule for Twinrix. It consists of 3 doses given within 4 weeks, followed by a booster dose at 12 months (0, 7 days, 21–30 days, and 12 months). The 4-dose schedule could benefit individuals needing rapid protection from hepatitis A and hepatitis B, such as people traveling to high-prevalence areas imminently.

Twinrix cannot be used for postexposure prophylaxis.

Last reviewed: June 25, 2023

No. Twinrix contains 50% less hepatitis A antigen component than Havrix, GSK’s monovalent hepatitis A vaccine [720 vs. 1440 El. U.], so the patient would not receive the recommended dose of hepatitis A vaccine antigen. For this reason, 3 doses of Twinrix must comprise the series.

Last reviewed: June 25, 2023

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