CLINICAL-EXPERIENCE WITH AN INACTIVATED HEPATITIS-A VACCINE

Clinical trials of an inactivated hepatitis A vaccine have encompassed 104 studies completed by December 1993 in 27 countries. Studies invol ved 50,677 subjects and administration of > 120,000 vaccine doses. Res ults show that the vaccine is safe, clinically well-tolerated, and hig hly immunogenic in all age groups. A seroconversion rate of 100% is ac hieved 1 month after primary vaccination. Vaccine-induced antibody tit ers persist after a primary vaccination course for greater than or equ al to 1 year with a single dose of 1440 ELISA units (EL.U.) in adults and after two doses of 360 EL.U. in children, A booster dose 6-12 mont hs after the first vaccine dose induces very high antibody titers, whi ch according to a mathematical model, are expected to protect against hepatitis A for >20 years. The vaccine is equally immunogenic when adm inistered simultaneously with other traveler vaccines, therefore enabl ing flexible and convenient vaccination against hepatitis A.