[How great is the risk of hepatitis due to travel? Retrospective study in the region of Zurich 1971-1976].

Between 1971 and May 1976 221 adult persons originating from the region of Zurich (Switzerland) developed acute viral hepatitis within the incubation period after a usually brief trip abroad. In those returning from European countries the ratio of HBsAg positive and negative infections was similar to that in the Canton of Zurich. From other continents the proportion of non-B hepatitis was 66-94%. On the basis of travel statistics the risk of this disease was assessed as highest in West Africa and Mexico; trekkers are especially exposed. The indication and dosage for immunoprophylaxis are discussed in detail.