COMBINATION HEPATITIS-A HEPATITIS-B VACCINE

The adult formulation of this combination hepatitis A-hepatitis B vacc ine contains 720 enzyme-linked immunosorbent assay units (EU) of forma lin-inactivated hepatitis A virus strain HM 175 and 20 mu g of recombi nant DNA yeast-derived hepatitis B surface antigen adsorbed onto alumi nium salts in 1ml for injection. The paediatric formulation contains h alf this dosage in 0.5ml for injection. The combination vaccine has be en shown to be highly immunogenic in healthy young adults after the fu ll dosage schedule of 3 doses at 0, 1 and 6 months. Trials in older ad ults and children indicate that immunogenicity is adequate in these gr oups also. The immunogenicity of the combination vaccine appears to be similar to that of hepatitis A vaccine and hepatitis B vaccine admini stered separately. Possible advantages for the combination vaccine rec ipient include fewer injections and lower costs. Local adverse reactio ns such as soreness at the injection site, redness and swelling occur often with the first dose of the series, but the incidence falls with subsequent doses. Local reactions are usually mild and transient, and reported systemic reactions (fatigue, headache) are thought not to hav e a causal link with the vaccine.