Epidemiological impact of Italian mandatory vaccination against hepatitis B in young adults

Background: Viral hepatitis caused by hepatitis B virus (HBV) is a leading cause of acute and chronic liver diseases worldwide. Objectives: In Italy, a mandatory vaccination policy was introduced in 1991 and was established for all newborns and 12-year-old individuals. In 2004, vaccination of 12-yearold adolescents was discontinued, and that of infants was maintained. Patients and Methods: We evaluated the seroprevalence of HBV markers in 806 individuals, who were vaccinated at birth or at 12 years of age, to assess the effectiveness of the national policy against HBV. Results: The overall prevalence of anti-HBs antibodies was 90.32% (95% confidence interval [CI]: 88.28-92.36%); 2.23% (95% CI: 1.21-3.25%) of the subjects were positive for both antibodies to HBsAg (anti-HBs) and antibodies to hepatitis B core antigen (anti-HBc), whereas 5.83% (95% CI 4.21-7.45) of the subjects were negative for all markers tested. Further, 1.61% (95% CI: 0.74-2.48%) of the subjects were positive for hepatitis B surface antigen (HBsAg). Conclusions: Our data provide additional evidence that HBV vaccination can confer long-term immunity when performed at birth and when performed for healthy adolescents; moreover, the results show the effectiveness of the application of a national vaccination strategy.