H. pylori is one of the most common chronic bacterial infections in humans. It is usually acquired in early childhood and persists for life unless treated.^[1][2] Global adult prevalence fell from 52.6% before 1990 to 43.9% during 2015–2022. Prevalence in children and adolescents has stayed at about 35% and has not declined significantly in any WHO region.^[3] In North America, prevalence is estimated at 30%–40%. Infection is more common in non-White racial and ethnic groups, in people raised in crowded or poor sanitary conditions, and in early-generation immigrants from endemic regions.^[4] In the largest contemporary US cohort, positivity was highest in non-Hispanic Black and Hispanic individuals and lowest in non-Hispanic White individuals.^[5]

• The crude global prevalence in adults fell from 52.6% (95% CI, 49.6%–55.6%) before 1990 to 43.9% (95% CI, 42.3%–45.5%) during 2015–2022.^[3]
  • On meta-regression, this was a 15.9% decline over 3 decades.^[3]
  • Significant reductions were seen in adults in the Western Pacific, Southeast Asian, and African WHO regions.^[3]
• A parallel meta-analysis found that global prevalence fell from 58.2% (1980–1990) to 43.1% (2011–2022).^[6]
  • Prevalence was relatively stable from 1991 to 2010 and declined most steeply during 2011–2022.^[6]
  • The largest decline was in the WHO African region.^[6]
• Prevalence is lower in younger age groups, in high-income countries, and in countries with broader universal health coverage.^[6]
• The decline is attributed to better socioeconomic conditions, sanitation, and hygiene, and to wider use of antibiotics and eradication therapy.^[2][3]
• Children and adolescents: prevalence was 35.1% (95% CI, 30.5%–40.1%) during 2015–2022.^[3]
  • There has been no significant reduction in any WHO region.^[3]
  • This stalled pediatric trend implies a continuing adult burden in future birth cohorts.
• Gastric cancer incidence has fallen globally and in countries where H. pylori prevalence has declined.^[3]

• Prevalence varies roughly 10-fold between countries.^[3]
• Prevalence tracks inversely with socioeconomic development and health-care coverage.^[6]
• During 2010–2022, pooled adult prevalence was highest in the WHO African (52.7%) and Eastern Mediterranean (52.6%) regions and lowest in the WHO European region (39.6%).^[3]
• National estimates range from about 9% (e.g., Finland, New Zealand) to more than 80% in several Latin American and Middle Eastern countries.^[3]

• Infection is acquired mainly in early childhood, usually before age 10.^[2][4]
• Prevalence is higher in older adults because of a birth-cohort effect.^[2]
  • Older cohorts had higher childhood transmission rates.
  • Adults do not have a higher rate of new acquisition.
  • In an older patient, infection most likely dates from childhood.
• Infection clusters within households. Mother-to-child and sibling-to-sibling spread are better supported than spousal transmission.^[2]

• Adults show a modest male predominance.^[7]

• The largest contemporary US dataset is a Veterans Health Administration cohort (n = 913,328; tested 1999–2018).^[5]
  • Overall H. pylori positivity was 25.8%.
  • Positivity fell from 35.9% (1999–2006) to 18.4% (2013–2018).
• Positivity declined in all racial and ethnic groups.^[5]
  • The excess burden in non-Hispanic Black and Hispanic compared with non-Hispanic White individuals persisted.
  • Demographics explained about 4.7% of the variation in positivity, mostly through race and ethnicity.
• An earlier VA study also found persistently high prevalence in African American and Hispanic veterans.^[8]

• Prevalence is high in first-generation immigrants from high-prevalence regions.^[4][9]
  • Examples include Latin America, East Asia, and Eastern Europe.
  • Their elevated risk is not reset by the low prevalence of the destination country.

• Study methods affect prevalence estimates.^[6]
  • Studies using serology report higher prevalence (53.2%) than studies using non-serologic tests such as the urea breath test and stool antigen test.
  • Serology reflects past or current exposure.
  • Serology cannot distinguish active infection from infection that has already been eradicated.^[1]
  • Seroprevalence studies therefore overestimate current active infection, so cross-study comparisons should account for the test used.
• Because of these demographic patterns, pretest probability of active infection is higher in the following US groups:^[4][5]
  • Non-Hispanic Black and Hispanic patients
  • Early-generation immigrants from endemic regions
  • People raised in crowded or low-sanitation settings
• Testing strategy is discussed in screening.