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Twinrix is a vaccine against hepatitis A and hepatitis B, manufactured by GlaxoSmithKline. Twinrix is administered over three doses.
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The name was created because it is a mixture of two earlier vaccines — Havrix, an inactivated-virus Hepatitis A vaccine, and Engerix-B, a recombinant Hepatitis B vaccine. Twinrix, Havrix and Engerix-B are registered trademarks of GlaxoSmithKline; if the same vaccine is available from others, it will have another name. Twinrix first entered the market in early 1997.
Administration schedule
Twinrix can be administered on the same schedule as monovalent Hepatitis B vaccine: at 0- 1- and 6- months. In some circumstances, an accelerated dosing schedule of 0- 7- and 21-to 30- days followed by a booster at 12 months can be used and is believed to have similar efficacy as the traditional schedule.
Efficacy
The CDC reports that clinical trials found the following levels of protection against Hep A and Hep B one month after each dose:
A: 93.8%, 98.8%, 99.9% B: 30.8%, 78.2%, 98.5%GlaxoSmithKline claims that its studies found 70% of subjects had antibodies against hepatitis B a month after just the first dose, however.