Is hepatitis B vaccination performed at infant and adolescent age able to provide long-term immunological memory? An observational study on healthcare students and workers in Florence, Italy

Universal vaccination programmes against Hepatitis B Virus (HBV) have significantly reduced the burden of the disease; nevertheless, HBV infection remains a relevant issue for high-risk subjects, such as healthcare workers (HCWs), who may potentially be exposed to blood or body fluids. Our study evaluates the long-term duration of the immunological memory of HBV vaccination 11–23 years after primary immunization by examining the response to booster doses in HCWs and students of health disciplines at Careggi Teaching Hospital in Florence (Italy). All participants (n = 2,203) had received a complete HBV immunization course in infancy or adolescence. Blood samples were collected to measure antibody levels against the HBV surface antigen (anti-HBs); an anti-HBs titre