HEPATITIS-A VACCINATION

The safety and immunogenicity of an inactivated hepatitis A virus vacc ine were assessed in 101 healthy adults. Seronegative persons with nor mal serum aminotransferase levels were grouped according to age: Group 1 (n = 24) and group 3 (n = 22) were between 18 and 40 years of age, and group 2 (n = 25) and group 4 (n = 30) were older than 40 years. Gr oups 1 and 2 received vaccine on a 0-, 1-, and 2-month schedule (sched ule A), and groups 3 and 4 received the vaccine on a 0-, 1-, and 12-mo nth schedule (schedule B). Of the 101 vaccinated subjects, 98 (97%) se roconverted with antibody titers to hepatitis A virus of greater-than- or-equal-to 20 IU per liter after the first dose, and all subjects ser oconverted after the second dose. The geometric mean titers a month af ter the third vaccine dose were significantly greater (P < .03) on bot h schedules for younger subjects (schedule A, 1,743 IU per liter, and schedule B, 7,882 IU per liter) than for older subjects (schedule A, 8 26 IU per liter, and schedule B, 4,279 IU per liter). Also, the differ ences in geometric mean titers a month after the third dose were signi ficantly greater (P < .001) for subjects in both age groups on schedul e B (group 3, 7,882 IU per liter, and group 4, 4,279 IU per liter) tha n for those on schedule A (group 1, 1,743 IU per liter, and group 2, 8 26 IU per liter). The hepatitis A virus vaccine was well tolerated, wi th mild discomfort at the injection site being the main side effect. T his vaccine is both safe and highly immunogenic.