Sero-epidemiology of hepatitis B markers in the population of Tuscany, Central Italy, 20 years after the implementation of universal vaccination.

Italy was one of the first industrialised countries to introduce a program of universal vaccination against hepatitis B in 1991. Twenty years later we verified the impact of universal immunisation on the epidemiology of hepatitis B infection by analyzing the prevalence of specific viral markers (anti-HBs, anti-HBc and HBsAg). The ELISA tests were performed on residual blood samples collected by 0.05% of the resident population aged 1-50 years in Tuscany (Italy). About 63% of subjects aged < 30 years were anti-HBs positive compared to about 25% in older subjects, without differences between genders. About 22% of subjects over 40 years were anti-HBc-positive compared to 5% in the younger age groups. The number of HBsAg-positive subjects was almost 10 fold higher in the unvaccinated age groups than in the cohorts involved in the universal vaccination program. The results of our study show the persisting high anti-HBs reactivity in vaccinated cohorts, while HBV markers related to natural exposure or persistent infection remain remarkably higher in older age groups. This sero-epidemiological study supports with prevalence data the downward incidence trend of acute hepatitis B highlighted by epidemiological surveillance systems, and corroborates the forecast for elimination of hepatitis B in Italy in a few decades.