Across western countries, the observed prevalence of H. pylori infection
ranges from 4% to 95% in adults and 4% to 82% in children, with estimates varying by
country and subpopulation within countries. Reported incidence ranges from 0 to 7.3%
per year in adults, with higher rates observed among travelers to high prevalence areas.
Reported incidence ranges from 0 to 1.7% per month in children under 2 years old and
0.11% to 16% per year in 2- to 18-year olds. Reported elimination rates in children
range from 0.37% to 35% per year. Evidence points to direct person-to-person contact
as the predominant mode of transmission. Factors linked to increased prevalence in
adults include residential crowding, institutionalization, and having hepatitis A virus. In
children, H. pylori infection is associated with age, indicators of poor socioeconomic
status such as residential crowding and parents’ education level, and migration from
high prevalence areas. Factors associated with elimination of H. pylori in childhood are
age, sex, ethnicity, and antibiotic use. Recurrence of H. pylori infection after successful
treatment is not frequently observed in western countries. Studies investigating the
relationship between intrafamilial clustering of H. pylori infection and H. pylori
recurrence have had inconsistent results. Development of cost-effective prevention
strategies requires more evidence pertaining to transmission pathways and risk factors,
as well as more effective treatments, particularly for high prevalence subpopulations.
Keywords: H. pylori infection, western countries, prevalence, incidence,
elimination, recurrence, transmission.
