Home / Ask The Experts / A 17-year-old received two doses of Twinrix (HepA-HepB), separated by one month. The second dose was six months ago and she is now 18 years old. Can she receive the third dose of Twinrix to complete the series?

Combination Vaccines
HepA-HepB (Twinrix, GSK)

A 17-year-old received two doses of Twinrix (HepA-HepB), separated by one month. The second dose was six months ago and she is now 18 years old. Can she receive the third dose of Twinrix to complete the series?

Yes. This was a vaccine administration error since Twinrix, a combination hepatitis A/hepatitis B vaccine, is not licensed for people younger than 18. However, the hepatitis A and hepatitis B components can be counted as valid doses. The third dose of the Twinrix series should be given at least five months after the second dose.

Last reviewed: July 15, 2023

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This page was updated on July 15, 2023.