Prevalence of hepatitis A virus infection in sewage plant workers of Central Italy: is indication for vaccination justified?

Prevalence of antibodies to hepatitis A virus (HAV) was studied in a group of 65 sewage plant workers living in Tuscany, Central Italy. In order to evaluate the effect of several confounders (age, place of birth, income, educational degree, sea-food consumption, etc.), subjects under study were matched with 160 other workers residing in the same area. Anti-HAV was detected in about 51% of sewage workers and 44% of other employees. The difference was not statistically significant. Both univariate and multivariate analysis showed that the main variables related to previous HAV infection were increasing age (P<0.001), birth in Southern Italy (P<0.01) and lower educational degree (P<0.001). Although other studies in Northern and Central Europe showed a slightly higher risk of infection in sewage workers versus general population, lack of evidence of occupational risk in Italy might be explained by the relative importance of a higher degree of viral circulation in the past. The changing epidemiology of HAV infection in Italy with increasing numbers of susceptibles in adults and the potential occupational risk suggest that the present indication to immunize sewage plant workers against hepatitis A should be maintained.