Changing epidemiology of parenterally transmitted viral hepatitis: results from the hepatitis surveillance system in Italy

Background. In 1991, compulsory hepatitis B virus vaccination and screening for anti-hepatitis C virus of blood banks were introduced in Italy. Aim. To evaluate the impact of preventive measures on the incidence and risk factors for parenterally transmitted viral hepatitis. Methods. Data from the surveillance system for acute viral hepatitis for the period 1985-99 were used. Temporal trends in distribution of reported risk factors were analysed by comparing three-year periods: 1987-89 and 1997-99. Results. The incidence (no. cases per 100, 000 population) of hepatitis B was 12 in 1985 and 3 in 1999; the incidence of hepatitis non-A, non-B decreased from 5 to I in the same period. These decreases were more evident among young adults and before rather than after 1991. Multiple sexual partners, other parenteral exposures and dental treatment remain the most common risk factors fop parenterally transmitted viral hepatitis. An increase in frequency over time was observed for other parenteral exposures, whereas a marked decrease was evident for blood transfusion and household contact with an HBsAg carrier. Invasive medical procedures continue to represent an important source of infection. Intravenous drug use was reported particularly by young adults with non-A, non-B hepatitis, with increased frequency over time. Conclusions. Non-immunologic measures for preventing hepatitis 8 and non-A, non B due to iatrogenic and other parenteral exposures, combined with hepatitis B virus vaccination, could further reduce parenteral transmission.