RESUMEN
To determine the duration of protection conferred by the hepatitis B (HB)vaccination and the necessity of a booster dose. Methods: Immediately after the initial bloodsampling, 252 youths (aged 18.8-20.5 years, 52% females) with a history of neonatal HBvaccination with one dose of the HB vaccine received a booster. Serum concentrations ofantibodies against the HB surface antigen were assessed in samples collected before and10-14 days after the booster. Seroconversion from concentrations <10 to ?10 IU/L weredefined as a positive immune response. Results: Of the 252 participants, 131 were sero-susceptible and 114 responded. Conclusions: Nearly 90% of young people preserved theirlong-term protection; the results of this study do not support the use of an HB boostervaccination