IMMUNOGENICITY OF THE HEPATITIS-B VACCINE, GENHEVAC-B, GIVEN IN 3 INJECTIONS (0, 1, 6 MONTHS) TO YOUNG SCHOOL-AGE TEENAGERS

Teenagers represent a high risk population to get hepatitis B infection by sexual or intravenous (TV drug use) transmission. Therefore, the vaccination of young teenagers, prior their exposition period, has emerged as a priority strategy to eradicate hepatitis B. Hundred and eighty three school boys (104) and girls (79), (mean age : 13.5 years) have received two injections of a recombinant hepatitis B vaccine, GenHevac B, at a 4-week interval followed by a booster injection six months after initiation. One month post third injection, almost all. subjects (99.5 %) had developed protective levels of anti-HBs (greater than or equal to 10 mIU/ml, geometric mean titres of 20 000 mIU/ml) and of anti-pre-S2 (greater than or equal to 30 mU/ml, geometric mean titres of 4 978 mU/ml) antibodies with no significant difference between sex. This three-dose immunization schedule can be easily completed during the school year. The very high anti-HBs antibody titres elicited suggest that a long lasting protection can be conferred. A booster injection could be postponed 10 years after primovaccination.