Epidemiology of hepatitis D virus (HDV) infection in an urban area of northern Italy

Abstract

Objectives: The introduction of vaccination against hepatitis B initially reduced the number of HBV (hepatitis B virus) and HDV (hepatitis delta virus) infections, but the decreasing trend of HDV infection seems to have stopped. The aim of this study was to assess the prevalence of HDV infection in the general population living in the catchment area of Legnano Hospital in northern Italy.

Methods: Of the 22,758 subjects tested in 2007-2008, the 488 who were HBsAg (hepatitis B surface antigen)-positive [including 107 (21.9%) of non-Italian origin] were subsequently tested for anti-HDV antibodies.

Results: Of the 488 subjects who tested positive for HBsAg, 24 (4.9%) were anti-HDV positive, all aged between 30 and 60 years. The difference in prevalence between males (7.1%) and females (1.9%) was statistically significant (p < 0.05), but not that between Italian (5.0%) and non-Italian patients (4.7%). The differences in anti-HDV seropositivity between the patients with acute (0%) and chronic infections (6.3%), and between the incident (2.5%) and prevalent cases (7.4%), were not statistically significant, but there was a significant difference (p < 0.01) between those with asymptomatic (2.1%) and clinically symptomatic infections (10.3%). Intravenous drug abuse was the main source of infection.

Conclusions: In the catchment area of our hospital, the prevalence of HDV infection does not seem to be due to patients of non-Italian origin, but to Italian patients who are not vaccinated against HBV and who survived the HDV epidemic of the 1970s and 1980s. Nevertheless, the increase in the number of immigrants from non-EU countries in recent years is soon likely to lead to a change in the epidemiology of HDV.