A prospective, randomized, comparative US trial of a combination hepatitis A and B vaccine (Twinrix®) with corresponding monovalent vaccines (Havrix® and Engerix-B®) in adults

In an open, randomized, multicenter, controlled clinical trial in the US, 773 adults were administered either a combination hepatitis vaccine (Twinrix: 720 EL.U inactivated hepatitis A antigen and 20 mcg recombinant hepatitis B surface antigen per milliliter) on a 0, 1, 6 month schedule or corresponding monovalent vaccines concurrently (Havrix, 1440 EL.U/ml of hepatitis A antigen at 0, 6 months and Engerix-B, 20 mcg of hepatitis B surface antigen at 0, 1, 6 months). Non-inferiority testing for the primary endpoint, severe soreness, and equivalence testing for the secondary endpoints, anti-HAV seroconversion and anti-HBs seroprotection, showed that safety and immunogenicity were comparable in the two groups.