<prompt> All of the following are true about Helicobacter pylori except:About 50 of world population affected85 of population is affected, in some developing countriesAll children in developing countries have immunity by five years of ageInfection is common in low socio-economic status  <response>: Ans. is c i.e., All children in developing countries have immunity by five years of ageRef: Harrison, 16the, p. 886,19the, p. 1038; Ananthanarayan, 9the, p. 400 Duodenal ulcer 80 and Gastric ulcer 60 are associated with H. pylori. Gastric adenocarcinoma, gastric MALT lymphoma, Autoimmune gastritis, Hyperacidity. Chronic gastritis in adults due to the reinfection and Treatment prevents the gastric lymphoma. Approximately 50 of world population and 85 of developing countries are affected by H. pylori. 