The incidence of Helicobacter pylori infection.

Acute Helicobacter pylori infection invariably passes undetected. Consequently, the incidence of infection has been determined indirectly from epidemiological studies. In adults of industrialized countries, an estimated 0.5% of the susceptible population becomes infected each year. This incidence has been decreasing over time. Thus, adults who currently harbour the organism are more likely to have been infected in childhood than adulthood. The incidence of H. pylori infection continues to be high (between 3% and 10% per year) in developing countries. Throughout the world, incidence of H. pylori infection appears to be higher in children than in adults, possibly due to lower standards of personal hygiene in younger populations.