Epidemiology of hepatitis A in Mediterranean countries.

Infection with hepatitis A virus (HAV) is still endemic in some Mediterranean areas. In most Northern Mediterranean countries, the incidence of acute icteric hepatitis in adults is increasing. This is due to the shifting of HAV infection to adulthood as a result of the decline of its overall prevalence due to improvements in socioeconomic, sanitary and hygienic conditions. The majority of adults remain susceptible and develop overt disease when infected, since the severity of disease is highly associated with age. Epidemics are now rare, but are more extensive when they do occur. They may sometimes be caused by accidental contamination of the water supply, but are usually due to contamination of food by diseased food-handlers or result from contaminated frozen foods. Outbreaks still may occur in day-care centres and in schools. Thus travelling to endemic areas is becoming the main source of HAV infection. Intrafamilial person-to-person spread also is an important source of infection. Transmission from children to parents and other adults may occur due to lack of immunity in the adult population. Selective immunization would further reduce the incidence of the disease. However, only inclusion of the vaccine in the routine programme of childhood immunization would guarantee the disappearance of hepatitis A.