Impact of universal vaccination programmes on the epidemiology of hepatitis B: 10 years of experience in Italy.

Ten years have elapsed since routine vaccination of infants and of 12-year-old adolescent was implemented in Italy. In this period, evidence has accumulated on the epidemiological impact of universal immunisation. Coverage is on average >90% and is >or=95% in many areas of the country. Incidence of acute hepatitis B, that was already declining before 1991, was further decreased by routine vaccination programmes. This is particularly evident in adolescents and young adults (cohorts involved by mandatory vaccination), while incidence shows little changes in older subjects according to data of the last years. Prevalence of hepatitis B virus (HBV) markers detected by sero-epidemiological studies on anonymous sera confirms both the very high coverage with hepatitis B vaccination and the virtual absence of chronic HBsAg carriers in cohorts involved by routine vaccination programmes. The system of passive surveillance on adverse events following hepatitis B vaccination supports the excellent safety record of hepatitis B vaccines. In a hyperendemic area of Southern Italy, where a pilot programme was firstly implemented, it was also possible to document the decline of the involvement of hepatitis B in chronic liver pathologies (from 48% in 1982 to 18% in 1997). If coverage rates are maintained at the present levels, elimination of HBV transmission in Italy may be envisaged in few decades.