Prevention of hepatitis C in Italy: lessons from surveillance of type-specific acute viral hepatitis. SEIEVA collaborating Group.

Using data from the surveillance system for type-specific acute viral hepatitis, the temporal incidence trend of non-A, non-B acute hepatitis and risk factors for acute hepatitis C have been evaluated in Italy. The association between hepatitis C and the potential risk factors (odds ratios, OR) was estimated using hepatitis A patients as controls. The independent roles of the different risk factors were estimated by multiple logistic regression analysis. The incidence of non-A, non-B acute hepatitis declined from 5 per 100 000 to 1 per 100 000 between 1985 and 1996. Anti-HCV data collected by SEIEVA since 1991 showed that 60% of patients with non-A, non-B acute hepatitis were positive for antibodies to the hepatitis C virus (anti-HCV) at the time of hospitalization. During the 6 months prior to the disease onset, the most frequently reported risk factors were multiple sexual partners, other parenteral exposure and intravenous drug use; transmission by blood transfusion declined from 20% in 1985 to 2% in 1996. On multivariate analysis, intravenous drug use (OR=35.5; 95% CI=23.1-54.4), surgical intervention (OR=4.6; 95% CI=3.3-6.5), dental treatment (OR=1.5; 95% CI=1.1-1.9) and two or more sexual partners (OR=2.2; 95% CI=1.6-3.0) were all independent predictors of hepatitis C. These findings indicate that HCV infection is decreasing in Italy. Intravenous drug use, multiple sexual partners, surgical intervention and dental therapy are the main modes of transmission.