Background: Increasing travel stresses the requirement for rapid protection against infections such as hepatitis A and B.
Methods: This randomised, multicentre study investigated an accelerated vaccination schedule using a combined hepatitis A and B vaccine (Twinrix, Smithkline Beecham Biologicals) compared with simultaneous administration of the two corresponding monovalent vaccines. The combined vaccine was administered on days 0, 7 and 21, whereas the comparison group received hepatitis A vaccine on day 0 and hepatitis B vaccine on days 0, 7 and 21. All subjects received booster vaccination at month 12.
Results: At month 1, 100% of subjects in the combined group and 99% of the controls were seropositive for anti-HAV antibodies. The corresponding seroprotection rates for anti-HBs antibodies were 82.0 and 83.9%, respectively. Examination of the 95% confidence intervals (CIs) for the treatment differences showed the two vaccines to be equivalent in terms of immunogenicity 1 week after the initial vaccination course. Just prior to the booster, the seropositivity rate for anti-HAV was 96.2% in the combined group and 95% in the control group. For anti-HBs, this was 94 and 91.6%, respectively. All subjects were seropositive for anti-HAV and seroprotected against hepatitis B at month 13. The anti-HAV GMCs were 9571mIU/ml with the combined vaccine and 5206mIU/ml in control subjects. The anti-HBs titre was 26002 and 29,196mIU/ml, respectively. Both groups had a similar reactogenicity profile.
Conclusions: The accelerated schedule of the combined vaccine provides a good immune response against hepatitis A and B antigens and is suitable for last minute immunisation.