The impact of the hepatitis B mass immunisation campaign on the incidence and risk factors of acute hepatitis B in Italy.

Background/aims: This study aimed to evaluate the impact of the campaign for hepatitis B mass immunisation of children and teenagers, introduced in 1991, on the incidence of and risk factors for hepatitis B in Italy.

Methods: Hepatitis B cases reported to the surveillance system for type-specific acute viral hepatitis (SEIEVA) during the period 1987-1997 were used to estimate incidence. To assess the association between potential risk factors and hepatitis B cases, hepatitis A cases generated by the same surveillance system were used as controls.

Results: During the period 1987-1997, 8275 acute hepatitis B cases were reported to SEIEVA. Hepatitis B incidence declined from 10.4/100,000 in 1987 to 2.9/100,000 in 1997. The fall was more evident before than after the introduction of compulsory vaccination against hepatitis B. The results of multivariate analysis showed that during the years 1995-1997, blood transfusion, intravenous drug use, surgical intervention, dental therapy, other parenteral exposures, multiple sexual partners, and being in the household of a chronic HBsAg carrier were all exposures independently associated with hepatitis B.

Conclusions: The strong association linking acute hepatitis B with iatrogenic exposures, which are more common in adults, suggests that the present immunisation strategy should be combined with the implementation of non-immunologic preventive measures.