Epidemiological Impact of Mandatory Vaccination against Hepatitis B in Italian 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 es- tablished for all newborns and 12-year-old individuals. in 2004, vaccination of 12-year- old adolescents was discontinued, and that of infants was maintained. patients and methods: we evaluated the seroprevalence of hbv markers in 806 individ- uals, 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 in- terval [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 ado- lescents; moreover, the results show the effectiveness of the application of a national vaccination strategy.