Decrease in incidence of hepatitis A infections in Germany.

The hypothesis of a decline in the incidence of hepatitis A infections in Germany in recent decades was confirmed by determining the prevalence of hepatitis A antibody (anti-HAV) in sera collected in 1965 and in 1975 under the same conditions in North Germany. The prevalence of anti-HAV correlated with the year of birth and was independent of the time of serum sampling. The force of infection fell from 0.04 in 1945 to 0.005 in 1965 as judged from a catalytic epidemic model with a sigmoidal decrease.