Long-term immunogenicity of hepatitis B vaccination in children and adolescents in a southern Italian town

Purpose

Universal anti-hepatitis B vaccination of infants and of 12-year-old children became mandatory in Italy in 1991. The purpose of this study was to evaluate the persistence of anti-hepatitis B surface (HBs) antibodies several years after a primary course of vaccination.

Methods

In 2010, anti-HBs titers were measured in all subjects aged between 5 and 25?years residing in a southern Italian town. Individuals with an anti-hepatitis B antibody concentration of 10?IU/ml or more were considered to be protected.

Results

Of the 671 subjects evaluated, 149 (30%) lacked protective antibodies. Fifty-three (29.4%) of the subjects had been vaccinated ??10?years earlier and 96 (30.3%) more than 10?years earlier (P?=?not significant). Subjects vaccinated in infancy were more likely to lack protective anti-HBs antibodies than subjects vaccinated at 12?years of age, regardless of the years elapsed since immunization.

Conclusions

Most subjects maintained protective antibodies for a considerable number of years after vaccination. Vaccination in adolescence results in more prolonged immunogenicity than vaccination in infancy.