Learning Objectives for this Presentation:
By the end of the presentation participants will understand that an accelerated schedule with a combined hepatitis A and B vaccine is effective and well-tolerated.

Background:
The US Advisory Committee on Immunization Practices recommends that individuals at high-risk for hepatitis A and B infection be vaccinated. An effective, well-tolerated, combined hepatitis A and B vaccine, administered using an accelerated schedule, offers a convenient way for those at high-risk for both infections to comply with the recommendations.

Objectives:
To determine the immunogenicity and safety of a combined hepatitis A and B vaccine utilizing an accelerated schedule.

Methods:
A prospective, open-label, randomized, comparative study investigating the immune responses of Twinrix® (≥720 EL.U inactivated hepatitis A antigen and 20 µg recombinant hepatitis B surface antigen per mL) at 0, 7, 21-30 days and 12 months and of Havrix® (1440 EL.U/mL inactivated hepatitis A antigen) at 0 and 12 months concurrently with Engerix-B® (20 µg/mL recombinant HBsAg) at 0, 1, 2 and 12 months, in seronegative healthy adults using an accelerated schedule.

Results:
Immune responses were similar between groups. The anti-hepatitis B seroprotection rate for the combined vaccine was 96.4% (95% CI: 92.7, 98.5) compared with 93.4% (95% CI: 89.0, 96.4) for the monovalent vaccines, one month after schedule completion. The anti-hepatitis A seroconversion rate was 100% in both groups. At Day 37, seroconversion rates for anti-hepatitis A were similar in both groups (98.5% and 98.6% for the combined and monovalent vaccine group, respectively), although anti-hepatitis B seroprotection rates were significantly (P<0.001) higher with the combined vaccine (63.2% versus 43.5%). All vaccines were well-tolerated.

Conclusions:
An accelerated schedule for the combined hepatitis A and B vaccine provides comparable immunogenicity and tolerability to equivalent monovalent vaccines, offering a convenient alternative for those at high-risk for hepatitis A and B.