Long-term persistence of seroprotection by hepatitis B vaccination in healthcare workers of southern Italy

Background: The impact of hepatitis B virus (HBV) vaccination campaigns on HBV epidemiology needs to be evaluated, in order to assess the long-term immunity offered by vaccines against HBV. Objectives: To evaluate the current status of anti-HBV vaccine coverage among healthcare workers (HCWs) in Southern Italy, and to determine the long-term persistence of antibodies to hepatitis B surface antigens (anti-HBs) in such a cohort of subjects. Patients and Methods: A longitudinal, retrospective seroepidemiological survey was conducted among 451 HCWs, who were working at or visiting, the Occupational Health Department of a city hospital, in Catania, Italy, between January 1976 and December 2010. Results: At the 30-year follow-up (mean follow-up 10.15 +/- 5.96 years, range 0.74-30), 261 HCWs had detectable anti-HBs titers indicating a persistence of seroprotection of 89.4% (out of 292 anti-HBs positive results, three months after vaccination). An inadequate vaccination schedule was the strongest predictor of antibody loss during follow-up (OR = 8.37 95% CI: 5.41-12.95, P < 0.001). A Kaplan-Maier survival curve revealed that the persistence of anti-HBs 30 years after vaccination, was 92.2% for high responders, while it was only 27.3% for low responders (P = 0.001). Conclusions: A good level of seroprotection persisted in 57.9% of the subjects after 30 years. Factors related to this immunization status confirmed the importance of vaccinating HCWs early in their careers and ensuring an adequate vaccination schedule. However, with particular reference to the low rate of hepatitis B vaccine coverage among HCWs in Southern Italy, the implementation of a new educational intervention as part of an active vaccination program is needed